-3  7// 


Digitized  by  the  Internet  Archive 

in  2007  with  funding  from 

IVIicrosoft  Corporation 


http://www.archive.org/details/engineerinwarwitOObondrich 


THE  ENGINEER  IN  WAR 


0 


McGraw-Hill  5ookG3mpaiiy 

Puj6fi^s/iers  qf3oo/^/br 

Electrical  World         TheLn^moerin^  and >fmin^  Journal 
En^in9€>riii^  Record  Engineering  News 

Railway  A^  G  azettp  Ameincan  Machinist 

Signal  Lngin.<?9r  American Eng|nper 

Electric  Railway  Journal  Coal  Age 

Metalluigical  and  Chemical  Engineering  Power 


THE  ENGINEER 
IN  WAR 

WITH  SPECIAL  REFERENCE  TO  THE  TRAIN- 
ING OF  THE  ENGINEER  TO  MEET  THE 
MILITARY  OBLIGATIONS  OF 
CITIZENSHIP 


REPRINTED,  WITH  REVISIONS  AND    ADDITIONS, 

FROM 

THE     ENOIVKKUIVO     RECORD 


BY 
P.  S.  BOND 

MAJOR,   COBPS  or   BNOINBERS,   V.  8.   ARMT 

MKMBER,   All.   SOC.   C.   S. 

HONOR  OEAOUATB.  ARMT  FIELD  ENGINEER  SCHOOL 

ORAOUATX  ARMT  STAFF  COLLEGE 


FiiiST  JBbiftiok 


McGRAW-HILL  BOOK  COMPANY,  Inc. 
239  WEST  39TH  STREET.     NEW  YORK 


LONDON:  HILL  PUBLISHING  CO.,  Ltd. 

6  &  8  BOUVERIE  ST..  E.  C. 
1916 


3^ 


Copyright,  191G,  by  the 
McGraw-Hill  Book  Company.  Inc. 


■THK     MAPL.B     PRBS8     YO»K    PA 


0 


PREFACE 

In  presenting  this  volume  to  the  engineering  profession,  the 
author  does  not  aim  to  provide  a  treatise  on  miUtary  field  engi- 
neering. A  number  of  excellent  manuals  and  text-books  are  in 
existence,  most  of  which  are  well  adapted  to  study  by  the  civilian 
engineer. 

After  all,  mihtary  field  engineering,  as  its  name  implies,  is  a 
practical  art  and  cannot  be  acquired  by  study  alone. 

Engineering  plays  so  important  a  part  in  all  the  operations  of 
warfare  that  it  is  perhaps  no  exaggeration  to  say  that  modern 
war  is  an  application  of  engineering  science  to  the  armed  conflicts 
of  states. 

Those  who  have  considered  our  military  policy  cannot  have 
failed  to  observe  how  greatly  it  depends  upon  the  voluntary 
service  of  our  citizens.  The  rights  and  privileges  of  citizenship 
carry  with  them  the  obligation  of  service  to  the  state.  But  the 
mere  tacit  recognition  of  a  duty  does  not  insure  its  efficient  dis- 
charge. If  we  acknowledge  a  duty  we  must  acknowledge  the 
necessity  of  preparing  to  perform  it.  If  we  do  not  prepare  we  are 
evading  our  duty.  Practical  patriotism  then  ceases  to  exist  and 
national  defense  becomes  a  term  without  meaning. 

In  this  voluntary  preparation  of  our  citizens  to  fulfill  their  obh- 
gations  to  the  state,  the  civil  engineer  will  play  an  important 
part.  The  non-professional  man  cannot  under  existing  condi- 
tions be  trained  in  any  reasonable  time  to  a  satisfactory  state  of 
efficiency  for  the  performance  of  the  many  and  varied  duties 
that  fall  to  the  lot  of  the  military  engineer.  The  nation,  there- 
fore, relies  on  the  civilian  engineers  and  contractors  of  America 
since  they  alone  are  qualified  to  prepare  in  time  of  peace  for  the 
performance  of  these  important  duties. 

In  the  following  pages  is  presented  a  brief  outline  of  the  rela- 

vii 

340148 


viii  PREFACE 

tion  of  engineering  to  the  conduct  of  war  and  the  adaptation  of 
the  principles  and  practices  of  civil  engineering  to  military  re- 
quirements. If  the  author  succeeds,  to  however  small  a  degree, 
in  arousing  the  interest  of  the  engineering  and  contracting  pro- 
fessions in  this  important  question  of  national  defense,  he  will 
feel  that  his  effort  has  not  been  in  vain. 

While  intended  primarily  for  the  engineer  and  contractor,  it 
is  hoped  that  the  subject  matter  of  this  volume  may  prove  of 
interest  to  all  who  contemplate  the  possibility  of  military  service 
to  the  country  in  case  of  need.  This  for  the  reason  that  the  prac- 
tice of  mihtary  field  engineering  is  not  limited  to  officers  of  engi- 
neers. Because  of  the  comparatively  small  number  of  engineers 
that  will  be  available,  any  officer  of  the  combatant  forces  may 
be  called  upon  to  practice  the  art  and  cannot  be  regarded  as 
properly  trained  unless  he  is  prepared  to  do  so. 

Cleveland,  O. 
ApHl,  1916. 


CONTENTS 

»  Page 

Preface vii 

CHAPTER  I 

Page 

The  Military  Policy  of  the  United  States 1 

False  sense  of  security  of  the  American  people. — Erroneous  ideas 
concerning  the  military  strength  of  the  nation. — War  the  field  of 
the  expert  and  professional. — Preparedness  a  form  of  national 
insurance. — Preparation  for  war  of  two  kinds. — Modern  theory 
of  war. — The  German  military  system. — Defective  policy  of  the 
United  States. — Prejudice  against  compulsory  training. — Organ- 
ized land  forces  of  the  United  States. — Expeditionary  forces  of 
foreign  powers  which  might  be  landed  on  our  shores. — Minimum 
strength  of  volunteer  army  for  effective  defense. — Numbers  and 
organization  of  engineer  troops  required. — Present  engineer 
personnel. — Need  of  trained  officers. — General  qualifications  of 
engineer  officers. — Necessity  for  large  reserve  of  partially  trained 
men. — Difficulty  of  training  volunteer  engineer  oflicers. — They 
must  be  obtained  from  the  engineering  and  contracting  profes- 
sions.— Relation  of  engineering  to  the  conduct  of  water. 

CHAPTER  II 

General  Duties  of  the  Military  Engineer  and  Economics  of 

Military  Engineering 12 

Thorough  working  knowledge  of  civil  engineering  essential  to  the 
military  engineer. — Military  and  civil  engineering  contrasted. — 
Classification  of  duties  with  respect  to  locality. — Duty  with  the 
mobile  army. — Classification  of  duties  of  mobile  engineer  troops. 
— Ideal  engineer  troops  trained  to  perform  all  duties. — Disad- 
vantages of  speciahzation  in  miUtary  field  engineering. — Broad 
general  training  demanded. — Economic  aspect  of  military  engineer- 
ing.— Time  the  controlUng  element. — Military  structures  essen- 
tially impermanent  in  their  nature. — Works  of  military  engineering 
must  meet  tactical  requirements. — Economics  of  peace  and  war 
compared. — Pioneer  works  must  be  simple  makeshifts. — Speed 
in  construction  demanded. — Formal  plans  rarely  used. — Methods 
of  promoting  speed  in  construction. 

ix 


X  CONTENTS 

CHAPTER  III 

Page 

Tools  and  Equipment  Employed  in  Military  Engineering 25 

Use  of  heavy  construction  plant  in  military  field  engineering 
usually  impracticable. — Necessity  for  preserving  mobility. — 
Utilization  of  local  materials. — Special  tools  for  field  fortification. 
— Engineers  equipped  with  ample  supply  of  simple  tools. — 
Commercial  and  special  types  of  tools. — Standard  pioneer  tools 
and  equipment  of  mobile  engineer  troops. — Motor  trucks  and 
light  construction  plant. — Conditions  which  govern  military 
pioneer  work. — Highest  expression  of  the  skill  of  the  military 
engineer. 

CHAPTER  IV 

Stream  Crossings 35 

Ability  to  cross  streams  essential  to  mobility. — Historical  examples. 
— Need  of  portable  bridge  equipage. — Ponton  equipage  of  U.  S. 
Army  described. — Methods  of  constructing  ponton  bridge. — 
Draw  spans. — Historical  example  of  use  of  ponton  equipage. — 
Improvised  bridges. — Adaptation  to  site  and  materials  available. 
— Seizure  of  existing  bridges. — Military  trestle  bridges,  frame 
and  pile.  Economic  spacing  of  trestles. — Selection  of  favorable 
site. — Three-  and  four-legged  trestles. — Materials  employed. — 
Field  pile  drivers. — Crib  supports. — Military  truss  bridges. — Spar 
bridges. — ^Long  spans  to  be  avoided. — Military  suspension  bridges. 
— Cables,  towers  and  anchorages. — Methods  of  placing  cables. — 
Stiffening  for  suspension  bridges. — Combinations  of  types. — 
Width  of  roadway. — Materials  for  floor  system. — Fords. — 
PracticabiUty  of  a  ford. — Improving  approaches  and  bottom. — 
Limiting  depths  of  fords. — Passage  on  ice. — Ferries,  when  em- 
ployed.— Use  of  ponton  equipment,  rafts,  etc. — Use  of  current 
as  motive  power  for  ferries. — Examination  and  repair  of  simple 
highway  bridges. — Factors  of  safety. — Poor  design  of  many 
existing  bridges. — Examination  of  bridges. — Approximate  for- 
mulae for  determining  carrying  power  of  floor  system. — Formulae 
for  strength  of  trestle  caps  and  roadway  bearers. — Strength  of 
simple  trusses. — Unusual  types  to  be  examined  with  special  care. 
Methods  of  strengthening  existing  bridges. — Placarding  bridges 
to  indicate  safe  load. 


CONTENTS  xi 

CHAPTER  V 

Page 

Military  Roads 63 

Roads  of  increasing  importance  in  conduct  of  war. — Motor 
transport  demands  good  roads. — Construction  of  paved  roads 
usually  impracticable  under  war  conditions. — United  States 
deficient  in  good  roads. — Improvement  of  existing  roads. — Ele- 
ment of  time  controls  location  and  construction  of  military  roads. 
— Nature  and  amount  of  traffic  to  be  considered. — Plant  employed 
in  construction. — Military  traffic  by  wagon  train  with  four-  and 
six-line  teams. — Improvements  efifect  slight  changes  in  speed  of 
transport. — Pavements  seldom  employed,  earth  roads  the  rule. — 
Methods  of  increasing  bearing  power  of  military  roads. — Gravel, 
rock-fill  and  corduroy  roads. — Relation  of  gradients  and  surfaces. 
— Width  of  road  for  militarj''  traffic. — Location  should  follow 
natural  gradients. — Heavy  cuts  and  fills  and  long  hauls  to  be 
avoided. — Permissible  grades  for  military  uses. — Concentration 
of  steep  grades  at  a  few  localities. — Economics  of  military  road 
location. — Preliminary  and  location  surveys. — Methods  and 
instruments  employed. — Removal  of  trees. — Sunlight  and  ventila- 
tion.— Types  of  culverts. — Drainage  of  roads. — Retaining  walls. — 
Switch-backs. — Maintenance  economics  of  military  roads. 

CHAPTER  VI 

Field  Fortificatiox  axd  Siege  Operations 72 

Strategical  and  tactical  fortifications  defined. — Purposes  of 
military  operations. — Concentration  of  force  at  critical  points. — 
Battle  the  logical  culmination  of  strategy. — Immediate  purpose 
of  field  fortification. — Fortifications  employed  in  ofifense  and 
defense. — Excessive  and  indiscriminate  use  destroys  the  aggressive 
spirit. — Correct  tactical  employment  essential. — Fortifications 
vary  with  weapons  employed  and  purpose  in  view. — Works  in- 
cluded under  field  fortification. — Functions  of  engineers  and  other 
troops  in  the  execution  of  field  fortification. — Works  must  be 
located  on  the  ground. — Considerations  involved  in  the  selection 
and  organization  of  a  defensive  position. — Compromise  of  ad- 
vantages and  disadvantages. — Fire  superiority  essential  to  success. 
— Simple  rifle  trenches  principal  feature  of  field  fortification. —  s 
Height  and  thickness  of  parapet. — Use  of  high  explosive  shells 
against  rifle  trenches. — Effects  of  rifle  and  shrapnel  fire. — Head 
and  overhead  cover. — Protection  against  grenades. — Revetments. 


xii  CONTENTS 

Paob 
— Drainage  of  trenches. — Traverses. — Bomb-proofs. — Conceal- 
ment from  view — how  effected. — Cover  for  supports  and  reserves. 
— Advantages  of  natural  cover, — Communicating  trenches  and 
galleries. — Mining  and  subterranean  operations  in  the  attack. — 
Preparation  of  the  foreground. — Obstacles. — Devices  employed 
to  retard  the  attacker. — ^Location  and  concealment  of  obstacles. — 
Artificial  illumination  of  the  battlefield. — Flares,  torches  and 
bonfires. — Searchlights,  bombs  and  rockets. — Aeroplanes  and 
balloons. — Power  plants  for  searchlights. — Machine  guns  and 
artillery. — Details  of  field  fortifications  simple  in  their  nature. — 
Unskilled  labor,  simple  tools  and  local  materials  employed. — 
Field  fortification  a  fine  art. — Practical  example  of  the  organization 
of  a  defensive  position. — Siege  operations  more  formal  than  field 
operations. — Effect  of  improvements  in  weapons  on  design  of 
siege  and  field  works, — Important  strategical  points  fortified  in 
time  of  peace. — Elaborate  nature  of  works  and  armament. — Guns 
of  large  caliber  required  in  the  attack, — The  investment  of  a  for- 
tress,— Selection  of  points  for  formal  attack, — The  bombardment. 
— Parallels  and  approaches. — Mining  and  countermining  in  the 
attack  and  defense. — Breaching  the  fortress. — The  assault. 

CHAPTER  VII 

Military  Demolitions .105 

Purposes  of  demolitions, — Destruction  to  be  limited  to  military 
necessities, — ^AU  troops  equipped  with  demolition  outfits. — Fire 
and  explosives, — High  explosive  shells. — Requirements  of  an 
explosive  for  miUtary  demolitions. — Commercial  explosives, — 
Use  of  fulminates  as  detonators. — Caps  and  fuses. — Tamping. — 
Reconnaissance  to  precede  demolition. — Partial  demoUtion  or 
temporary  disablement  of  structures, — Structures  attacked  at 
weakest  points, — Proper  charge  of  explosive. — Demolition  of 
timber  structures, — Demolition  of  framed  structures. — Bridges, 
roads  and  railroads, — Buildings,  telegraph  lines,  woods. — Arches, 
canal  locks, — Destruction  of  miscellaneous  supplies, — Demolition 
of  obstacles. 

CHAPTER  VIII 

Military  Recoxxaissance,  Sketching  .^nd  S^JRVE■i^^-G 113 

Importance  of  maps  in  the  conduct  of  war. — Territorial  extent 
of  modem  military  operations, — Game  of  war  played  on  a  map. — 


CONTENTS  xiii 

Page 
Need  of  maps  in  all  operations. — All  officers  should  be  able  to 
read  and  make  maps. — Military  mapping  duties  of  the  engineers. 
— Need  of  maps  in  advance  of  operations. — Deficiency  of  good 
maps  of  western  hemisphere. — Proper  scales  of  maps  for  strategical 
and  for  tactical  purposes. — Scales  for  military  sketches. — E.xten- 
sive  mapping  required  subsequent  to  outbreak  of  hostilities. — 
Methods  employed  for  military  mapping  of  large  areas. — Employ- 
ment of  civilian  surveyors. — Methods  employed  for  military 
mapping  at  the  front. — Adaptation  of  the  plane  table  method. — 
Simple  instruments  employed. — Methods  of  military  plane  table 
sketching. — Measurement  of  distances,  angles,  slopes  and  eleva- 
tions.— "Map  distances"  defined. — Fixing  the  contour  points. — 
The  "normal  system"  for  military  sketching. — Location  of  critical 
points. — The  skeleton  or  control  of  a  sketch. — Valleys  and  stream 
lines,  hills  and  ridges. — Conventional  signs  employed  in  military 
mapping. — Information  recorded  on  the  map. — Reconnaissance 
reports. — Area  or  distance  covered  in  a  day. — Combined  sketching 
for  large  areas. — Methods  of  control  and  coordination. — Correc- 
tion and  amplification  of  existing  maps. — Map  reproduction. — 
Actinic  printing  processes. — The  hectograph. — Lithography. — Brief 
description  of  hasty  method  of  contouring. — Ability  to  read  a 
map  essential  to  all  officers  and  non-commissioned  officers. — 
Facilijty  acquired  only  by  long  practice. — Problems  to  be  solved 
and  questions  answered  on  the  map. — VisibiHty  problems. — 
Solution  of  visibility  problems. — Photography  for  military  pur- 
poses.— Military  landscape  sketching. 

CHAPTER  IX 

Military  Sanitation 136 

Fighting  efficiency  of  troops  dependent. on  the  maintenance  of 
their  health. — Losses  due  to  sickness  in  .past  wars  exceeded  those  by 
battle. — Influence  of  camp  epidemics  on  progress  of  civilization. — 
Sanitary  functions  of  the  engineers. — Sanitary  considerations  in 
selection  of  sites  for  mobilization  camps. — Sanitary  measures 
should  be  planned  in  advance. — Instruction  of  troops  in  personal 
hj'giene. — Water  supply,  drainage  and  sewage  disposal. — Ventila- 
tion and  shelter  for  camp  sites. — Necessity  for  good  water  supply. 
— Water-borne  diseases. — Flies  and  mosquitoes. — Water  supply 
methods. — Amount  of  water  consumed. — Regulation  of  water 
consumption. — Gravity  supply. — Storage  reservoirs,  settling  basins. 


xiv  CONTENTS 

Page 
tanks,  etc. — Rivers  and  lakes. — Intakes. — Wells. — Mechanical 
filters. — Chemical  purifiers. — Distillation  and  boiling. — Water  for 
bathing. — Pumping  plants. — Dry  sewage  methods. — Latrines. — 
Incineration. — The  pail  system. — Cesspools  and  septic  tanks. — 
Disposal  of  kitchen  waste. — Relation  of  military  to  civil  sanitation. 

CHAPTER  X 

The  Mobilization  op  Material  Resources 142 

Importance  of  the  problem. — Supplies  of  all  kinds  required. — 
Our  transportation  systems. — Vast  unorganized  resources  of  the 
United  States. — Inefficiency  displayed  in  supplying  munitions 
for  European  war. — Benefits  to  be  derived  from  the  experience. — 
Probable  needs  to  be  ascertained. — Investigation  of  sources  of 
supply. — Measures  to  stimulate  production. — Commercial  and  spe- 
cial materials. — Examples. — Necessity  for  a  reserve  of  mate- 
rial to  be  kept  on  hand. — Amount  of  reserve  supply — how  de- 
termined,— Measures  to  be  based  on  greatest  probable  needs. 
— Ultimate  possible  needs. — Supplies  for  military  uses  should 
conform  to  commercial  standards  as  far  as  practicable. — 
Supplies  and  equipment  which  can  be  commandeered. — Possible 
output  of  all  manufactories  to  be  investigated. — Time  required 
to  place  factories  on  an  efficient  basis  for  producing  munitions 
of  war, — Plans  and  specifications  should  be  submitted  to  manu- 
facturers for  scrutiny  and  revision. — Experimental  samples 
to  be  produced. — Detailed  instructions  as  to  methods  of  fabrica- 
tion.— Reserve  supply  of  special  tools,  machines,  gauges  and 
patterns. — Manufacturers  to  assist  in  the  investigation. — Mili- 
tary significance  of  location  of  many  industrial  plants  close 
to  Atlantic  seaboard. — Mobilization  of  industrial  personnel. — 
Readjustment  of  industrial  conditions  in  time  of  war. — Employ- 
ment of  women  in  industry. — Needs  of  the  civil  population  during 
war. — Effect  of  war  conditions  on  certain  industries. — Govern- 
mental aid  necessary  to  maintain  confidence  and  prevent  hardship. 
— Assistance  of  the  engineering  profession  in  the  mobilization  of 
material  resources. — ^Labor  unions. — Prevention  of  strikes. — 
MobiUzation  of  transportation  systems.— Use  of  expert  personnel  of 
the  railroads. — Power  of  the  Government  to  regulate  industry  in 
time  of  war. — Prices  for  war  material, — Mobilization  plans  to  be 
kept  up  to  date. — ^Location  and  capacity  of  governmental  munition 
plants. — Tendency  of  the  American  people  to  regard  the  question 


CONTENTS  XV 

Page 
lightly. — Are  we  not  short  sighted? — Military  operations  fre- 
quently hampered  by  lack  of  adequate  supplies  and  equipment. — 
Examples  from  the  European  war. — Advantage  of  the  United 
States  in  the  matter  of  material  resources. — Wisdom  of  bringing 
this  advantage  to  bear  in  case  of  war. — Unlimited  supplies  of 
artillery  ammunition  will  accomplish  greatest  results  with  minimum 
loss  of  life. 

CHAPTER  XI 

How  May  the  Engineers  and  Contractors  op  America  Prepare  To 

Meet  the  Military  Obligations  op  Citizenship? 152 

National  defense  dependent  on  voluntary  service. — Practical 
patriotism. — Engineer  officers  must  be  both  soldiers  and  engineers. 
— Necessity  of  previous  technical  training  for  volunteer  engineers. 
— Contractors  possess  many  of  necessary  qualifications. — Contract 
foreman  and  laborers. — Knowledge  of  tactics  and  military  methods 
essential. — Engineering  profession  should  take  interest  in  national 
defense. — Indifference  of  American  people. — Necessity  for  devising 
a  system  of  training. — Study  must  be  supplemented  by  practical 
outdoor  training. — Aid  which  engineering  societies  may  render. — 
Instruction  in  tactics  and  practical  miUtary  engineering  in  technical 
schools. — Governmental  aid. — Business  men's  camps. — Difficulties 
in  matter  of  attendance. — Cooperation  of  employers. — Civilian 
employees  of  federal,  state  and  municipal  governments. — Field 
training  in  the  regular  army. — Sites  available  for  civilian  instruc- 
tion camps. — OutUne  of  proposed  course  of  instruction. — Corre- 
spondence courses. — Practical  military  problems. — Reading  of 
greatest  value  in  connection  with  original  and  independent  effort. 
— Description  of  the  applicatory  method  of  military  instruction. — 
Commissions  in  volunteer  engineers. — Success  dependent  on 
interest  and  voluntary  cooperation  of  civilian  engineers. 

Bibliography 162 

Glossary  op  Terms 170 

Index 177 


XI 


V 


THE  ENGINEER  IN  WAR 

CHAPTER  I 
THE  MILITARY  POLICY  OF  THE  UNITED  STATES 

The  principal  problem  confronting  the  nation  today  is  that  of 
preparedness  for  defense.  There  is  an  indication  that  our  people 
ire  awakening,  partially  at  least,  from  the  sense  of  false  security 
in  which  they  had  been  blissfully  reposing  for  many  years.  This 
Feeling  of  security  which  has  hitherto  been  characteristic  of  the 
American  people  is  the  result  largely  of  the  ultimate  success  that 
bas  attended  our  several  armed  conflicts.  The  nation  has  not 
yet  experienced  the  chastening  discipline  of  defeat.  There  is 
also  prevalent  an  idea  that  great  resources  in  men  and  materials 
of  themselves  constitute  great  military  strength.  As  to  the 
first  of  these  popular  ideas  it  is  to  be  remarked  that  our  successes 
have  been  unearned.  We  have  triumphed,  not  because  of  our 
efficiency,  but  in  spite  of  our  inefficiency.  The  systematic  and 
intelligent  progress  that  have  marked  our  industrial  growth  have 
been  conspicuously  lacking  in  our  military  affairs.  We  have 
never  entered  the  lists  with  a  powerful  nation  trained  for  the 
conflict  and  able  to  turn  its  strength  against  us.  To  this  fact 
we  have  more  than  once  owed  our  national  existence.  Our 
popular  histories  record  in  glowing  words  our  successes  but  they 
do  not  record  the  enormous  and  unnecessary  expenditures  of 
blood  and  treasure  with  which  these  successes-  have  been  pur- 
chased nor  the  grave  risks  of  national  dissolution  which  we  have 
incurred.  For  a  proper  appreciation  of  the  misconception  that 
great  resources  constitute  great  strength  we  have  only  to  con- 

1 


.  THfi-ETfGJNEER  IN  WAR 


sider.  the  Ga\,se  oi  .China,  the*  oiost  populous  nation  on  earth  and 
poscfes^*6FV^'t  uiioi?g&iii2€fd  resources,  yet  utterly  lacking  in 
mihtary  strength  and  powerless  to  protect  herself  from  aggression. 
The  military  strength  of  a  government  at  any  instant  is  only  the 
power  it  can  bring  to  bear  upon  the  field  of  battle. 

War  today  is  one  of  the  most  highly  developed  of  the  sciences — 
the  field  of  the  expert  and  the  professional.  This  being  the  case 
there  is  more  than  at  any  time  in  the  past  a  need  of  adequate 
preparation  in  advance  of  the  outbreak  of  hostilities.  Prepara- 
tion for  defense  is  merely  a  form  of  national  life,  fire  or  accident 
insurance.  When  the  conflagration  has  broken  forth  it  is  too 
late  to  organize  the  fire  insurance  company  or  the  fire  department. 
Fire  is  an  unreasoning  element  which  strikes  alike  the  insured  and 
uninsured.  War  is  destruction  endowed  with  judgment  and 
perception,  it  prefers  dehberately  to  select  the  uninsured. 

The  preparation  for  war  is  of  two  kinds:  one  of  mat€rial  things 
• — the  construction  of  battleships,  submarines  and  coast  defenses, 
the  fabrication  of  weapons,  munitions  and  supplies;  the  other, 
the  organization  and  training  of  the  people.  While  both  arc 
necessary,  the  latter  is  the  more  important  as  well  as  the  more 
difficult  to  provide. 

The  modem  theory  of  war  as  exemplified  in  the  practice  of  the 
so-called  military  nations,  is  that  all  the  resources  of  the  state — 
moral  physical  and  intellectual — should  be  at  the  disposal  of  the 
government.  War  is  the  most  critical  condition  of  the  modern 
state  with  its  highly  developed  and  peculiarly  sensitive  and  vul- 
nerable industrial  and  commercial  systems.  For  the  successful 
prosecution  of  a  conflict,  on  which  the  very  fate  of  the  nation 
may  depend,  every  ounce  of  its  strength  should  be  available. 
The  aim  is  to  strike  quickly  with  all  the  force  at  the  nation's 
command.  That  state  is  best  prepared  which  can  most  rapidly 
bring  to  bear  its  resources  in  men  and  materials.  In  this  modern 
theory  is  involved  the  principle  that  every  able-bodied  male 
citizen  owes  to  the  state  the  obligation  of  service.  This  principle 
is  not  incompatible  with  democratic  ideals  and  is  recognized  in 


THE  MILITARY  POLICY  OF  THE  UNITED  STATES  3 

theory  by  our  own  constitution.  The  greater  the  benefits  con- 
ferred by  the  government,  the  greater  the  resulting  obUgation 
of  the  citizen.  The  nearest  approach  to  perfection  in  the  appli- 
cation of  this  theory  of  war  is  exhibited  by  the  German  Empire. 
Whatever  may  be  our  personal  sympathies  we  can  not  withhold 
our  admiration  for  the  splendid  efficiency  of  the  German  mili- 
tary machine  and  the  complete  mobilization  of  the  material  re- 
sources of  the  Empire.  The  history  of  this  state  shows  that  the 
military  system  is  the  mother  of  the  German  Empire.  Bis- 
marck, the  statesman,  planned  the  greater  Germany,  but  Von 
Moltke,  the  soldier,  created  it  when  he  destroyed  in  two  short 
campaigns  tho  military  power  of  Austria  and  France. 

The  German  system,  then,  may  be  regarded  as  the  most 
effective  policy  of  national  preparation  for  war,  and  it  will  be  of 
interest  to  consider  it.s  principal  features.  In  the  first  place  the 
training  of  the  personnel  is  what  is  known  as  universal,  which  is 
to  say  that  it  is  applied  to  a  very  large  proportion  of  the  male 
inhabitants.  In  the  second  place,  it  is  compulsory.  In  the  third 
place,  it  is  regular.  The  standing  army  constitutes  a  school  in 
which  all  men  receive  in  their  youth  the  regular  training  necessary 
to  qualify  them  for  field  service,  after  which  they  are  passed  to 
the  reserves  and  allowed  to  pursue  the  vocations  of  civil  life, 
being  occasionally  called  out  for  short  periods  of  training.  They 
thus  constitute  a  military  asset  until  they  reach  the  age  of  physical 
disabiUty,  but  are  not  withdrawn  from  the  pursuits  of  civil  life. 
This  excellent  system  of  general  training  is  supplemented  and 
made  effective  by  governmental  control  of  the  material  resources 
of  the  country,  including  the  transportation,  agricultural  and 
industrial  systems,  to  the  end  that  they  may  be  instantly  brought 
into  efficient  service  in  case  of  war.  This  mobilization  of  the 
resources  of  the  country,  both  material  and  personnel,  is  controlled 
by  a  large  corps  of  highly  trained  officers  known  as  the  Great 
General  Staff.  Such,  in  brief,  is  the  German  system,  which 
exemplifies  the  modern  theory  hereinbefore  referred  to,  that  all 
the  resources  of  the  state,   moral,   physical  and   intellectual, 


4  THE  ENGINEER  IN  WAR 

should  be  at  the  immediate  disposal  of  the  government  in  case 
of  war.  Such  a  system  is  most  effectual  under  a  highly  central- 
ized, indeed  a  despotic  form  of  government.  But  it  is  not  limited 
to  such,  inasmuch  as  France,  a  repubUc,  has  adopted  and  cafried 
out  practically  the  same  system  as  Germany.  On  the  other  hand, 
China,  hitherto  and  possibly  again  to  be  one  of  the  most  despotic 
of  governments,  has  no  military  poUcy  whatever,  unless  peace 
at  any  price  may  be  so  called. 

In  contrast  with  the  efficient  systems  of  the  continental  powers 
of  Europe  the  defects  of  our  own  military  policy  are  most  glaring. 
"Whether  we  may  be  willing  to  admit  it  or  not,'*  says  Gen. 
Upton,  "in  the  conduct  of  war,  we  have  rejected  the  practice  of 
European  nations  and,  with  little  variation,  have  thus  far 
pursued  the  pohcy  of  China."  It  is  not  the  purpose  of  the  author 
to  dwell  at  length  upon  the  defects  of  our  system  nor  to  detail 
the  mistakes  that  have  characterized  the  conduct  of  our  past 
wars,  but  to  look  hopefully  to  the  future.  In  recent  years  there 
has  been  a  marked  improvement  in  our  national  defense.  The 
regular  army  has  been  enlarged,  a  general  staff  has  been  estab- 
hshed,  and  the  system  of  instruction  for  both  officers  and  men 
has  been  greatly  extended  and  improved.  The  militia  of  the 
several  states  has  been  brought  into  closer  relation  with  the 
federal  government,  and  better  methods  of  instruction  inaugu- 
rated. We  are  still,  however,  very  far  below  European  standards. 
Our  mihtary  policy  has  not  kept  pace  with  the  growth  of  our 
population,  the  advance  in  the  science  of  war  and  the  constantly 
augmented  strength  of  other  nations. 

There  is  promise  that  the  present  agitation  for  national 
defense  may  result  in  further  strengthening  and  improvement  of 
our  organized  forces,  but  the  outcome  is  still  uncertain  and  our 
discussion  is  based,  therefore,  on  the  policy  as  it  exists  today. 
This  pohcy  is  perhaps  the  logical  outcome  of  a  firmly  rooted 
national  prejudice  against  large  standing  armies.  Our  form  of 
government  and  the  spirit  of  our  people  at  present  preclude  that 
efficient  form  of  preparation  adopted  by  the  Europeans  and  char- 


THE  MILITARY  POLICY  OF  THE  UNITED  STATES  5 

acterized  by  large  standing  armies  and  reserves  and  compulsory 
regular  training.  It  is  doubtful  if  anything  short  of  a  great 
national  calamity  will  cause  a  radical  change  in  this  poUcy.  We 
can  and  should,  however,  do  everything  possible  under  the  re- 
strictions imposed  by  the  temper  of  our  people  to  make  the 
national  defense  effective,  or  rather  to  decrease  its  inefficiency, 
to  plan  for  the  future  and  avoid  some  of  the  mistakes  of  the 
past. 

Our  organized  land  forces  at  present  consist  of  a  well-trained 
standing  army  of  about  100,000  men,  and  a  partially  trained 
national  guard  having  an  enrolled  strength  of  about  130,000  and 
an  effective  strength  less  than  this  figure.  Neither  organization 
is  provided  with  a  reserve.  The  demands  of  our  oversea  posses- 
sions considerably  reduce  the  number  of  regular  troops  available 
for  home  defense.  In  all,  we  might  muster  for  the  field  army  in 
case  of  invasion  125,000  men,  most  of  whom  would  be  only 
partially  trained — not  first-line  troops  as  that  term  would  be 
understood  in  Europe.  This  is  not  an  imposing  array  certainly, 
for  the  greatest  of  nations,  having  some  18,000,000  men  capable 
of  bearing  arms.  For  the  rest,  we  should  have  to  depend  upon 
volunteers  or  conscripts,  men  with  Uttle  or  no  training,  who 
would  require  months  to  fit  them  even  for  defensive  warfare 
against  the  highly  trained  troops  of  a  foreign  foe.  In  this  con- 
nection it  will  be  of  interest  to  note  that  the  British  government 
has  recently  resorted  to  compulsory  service  and  has  announced 
the  policy  that  hereafter  no  troops  not  having  at  least  one  year 
of  constant  training  will  be  sent  to  the  front.  Such  is  the  result 
of  the  bitter  experience  derived  from  opposing  imperfectly 
trained  volunteers  to  the  highly  trained  German  regulars.  At 
present  our  chief  reliance  for  defense  is  in  these  same  imperfectly 
trained  volunteers.  The  prospect  is  not  a  cheerful  one  nor  cal- 
culated to  arouse  our  pride  and  fill  us  with  confidence. 

What  would  be  required  in  the  event  of  war?  This,  of  course, 
is  problematical.  The  nations  of  Europe  assume  in  advance  that 
their  entire  strength  may  be  required,  and  this  is  actually  the 


Strength  of  regular 

First 

Time. 

Second 

Time. 

force             : 

expedition.    , 

»  1 

da^    , 

expedition 

1  days 

1                                  1 
4,320,000      ' 

72,000 

20.7 

I 

'    108.000 

'40.4 

5,000,000 

161,000 

15.8 

,    243,000 

30.0 

5,000,000 

387,000 

15.8 

440,000 

(30.8 

695,000 

170,000 

14.0 

27.0 

2,600,000 

91,000 

18.3 

'    136,000 

35.0 

2,212,000 

96,000 

22.5 

143,000 

41.0 

5,000,000 

38,000  1 

20.5 

'      66,000 

40.0 

6  THE  ENGINEER  TN  WAR 

case  of  several  of  them  in  the  present  war.  A  protracted  struggle 
with  a  combination  of  foreign  powers  might  call  for  several 
miUions  of  men.  The  following  table,  prepared  by  the  General 
Staff  of  the  Army,  shows  the  expeditionary  forces  which,  in  the 
event  that  our  navy  were  defeated  or  bottled  up,  could  be  landed 
on  our  shores: 

State 

Austria 

France 

Germany 

Great  Britain .... 

Italy 

Japan 

Russia 

To  repel  possible  attacks  of  this  nature  the  General  Staff 
recommends  the  following: 

500,000  men  at  the  outbreak  of  war. 
500,000  men  in  ninety  days  thereafter. 
500,000  men  to  replace  casualties. 

For  the  purposes  of  our  discussion  then,  we  will  assume  that  a 
volunteer  army  of  1,250,000  men  will  be  required.  This  is  a 
modest  figure.  It  is  to  be  noted  that  it  contemplates  strategical 
defensive  measures  in  particular.  Such  a  force  would  be  totally 
inadequate  to  a  foreign  invasion  except  of  a  weak  neighbor, 
such  as  Mexico.  It  would  not  serve  to  maintain  the  "Monroe 
Doctrine"  in  the  face  of  determined  aggression  by  a  great 
foreign  powder,  especially  when  the  inadequacy  of  our  water 
transport  facilities  is  considered.  Preparedness  for  defense  of 
our  own  territory  does  not,  of  course,  preclude  the  possibility  of 
offensive  tactical  operations,  and  it  is  the  blows  which  we  strike 
and  not  those  which  we  fend  that  win  the  victory.  But  it  does 
condemn  us  in  advance  to  suffer  all  the  ruin  and  agony  of  war  on 


THE  MILITARY  POLICY  OF  THE  UNITED  STATES  7 

our  own  soil  in  case  of  aggression  by  a  great  foreign  power. 
And  we  should  not  overlook  the  fact  that  our  Atlantic  seaboard, 
the  most  populous,  wealthy  and  highly  developed,  and  hence 
the  most  vulnerable  portion  of  our  domain,  might  be  the  theater 
of  the  early  stages  of  war.  Whatever  the  final  outcome  of  the 
conflict,  the  ruin  and  suffering  in  our  own  fair  land  would  be  very 
great.  Germany,  the  greatest  of  the  military  nations,  does  not 
entertain  the  defensive  policy  of  preparedness.  Her  theory  is 
that  an  active  offensive  is  the  best  defense  and  her  thorough 
preparation  has  enabled  her  at  the  outset  to  carry  the  war  into 
the  enemies'  territory  and,  thus  far,  to  Jceep  it  there.  Thus  is 
Germany  spared  the  ravages  of  war  on  her  own  soil. 

Without  entering  into  the  intricacies  of  army  organization  suf- 
fice it  to  assume  that  this  force  would  consist  of  62  divisions  of 
about  20,000  men  each.  These  would  be  further  organized  into 
field  armies  consisting  of  two  or  more  divisions,  say  20  in  all. 
And,  finally,  they  would  constitute  four  main  armies,  each  in- 
cluding five  field  armies. 

Now  let  us  consider  the  engineer  troops  that  would  be  required 
for  service  with  this  force.  The  proportion  of  engineer  troops 
with  an  army  in  the  field  which  experience  indicates  to  be  correct 
is  from  J^o  to  }{q.  Considering  the  vast  extent  of  our  territory, 
the  generally  poor  condition  of  our  roads  and  the  inexperience  of 
our  volunteer  troops,  it  is  certain  that  the  services  of  engineer 
troops  will  be  urgently  needed.  It  is  safe  to  say  that  no  army 
has  ever  had  an  excess  of  engineer  troops.  The  demands  upon 
them  have  invariably  been  greater  than  their  capacity.  Our 
organization  contemplates  one  battalion  of  engineers  with  each 
division,  and  an  additional  battalion  as  auxiliary  to  each  field 
army.  Each  of  the  four  main  armies  would  require  as  a  minimum 
two  additional  battalions.  Besides  this  there  would  be  required 
engineers  on  the  lines  of  communication  and  at  the  main  supply 
depots.  The  number  and  efficiency  of  our  railroads  would  oper- 
ate to  reduce  the  number  of  engineers  required  on  the  Unes  of 
communication,  unless  these  were  subject  to  attack  by  the  enemy 


8  THE  ENGINEER  IN  WAR 

— a  not  unlikely  contingency.    Let  us  assume  then  the  following 
force : 

Battalions 

Attached  to  divisions 62 

Attached  to  field  armies 20 

Attached  to  armies 8 

On  lines  of  communication  and  at  depots 10 

Total 100 

These  battalions  would  include,  on  the  average,  500  men  and 
14  officers  each.  Total,  50,000  men  and  1,400  officers.  This 
gives  a  proportion  of  approximately  J^s  for  the  assumed  force 
of  1,250,000  men,  which  is  none  too  large.  In  addition  to  this, 
a  considerable  number  of  engineer  officers  would  be  required  for 
service  in  the  War  Department  and  on  the  staffs  of  the  generals 
commanding  divisions  and  armies.  In  many  of  the  divisions  the 
senior  engineer  officer  with  the  troops  would  act  also  on  the  staff 
of  the  commanding  general.  The  following  engineer  personnel 
(officers)  is  assumed  as  necessary  for  staff  duty: 

On  division  stafifs 24 

On  field  army  staffs 32 

On  army  staffs 12 

On  lines  of  communication  and  at  depots 12 

At  the  War  Department  (General  Staff  and  Office  of  Chief 

of  Engineers) 20 

Total 100 

To  recapitulate,  say — 

50,000  men 
1,500  officers 

The  regular  army  at  present  includes  12  companies  of  engineers 
and  248  officers.  There  are  very  few  organized  engineer  units  in 
the  national  guard.  New  York  has  two  battalions  of  4  companies 
each,  and  Ohio  a  battalion  of  4  companies.  Certain  other  states 
have  companies  or  detachments.  In  all,  the  guard  might  muster 
not  to  exceed  6  battalions  at  war  strength,  with  84  officers.  The 
regular  engineers  might,  with  some  delay  and  loss  of  efficiency, 


THE  MILITARY  POLICY  OF  THE  UNITED  STATES  9 

be  expanded  into  6  battalions.  Thus  the  total  available  person- 
nel of  the  regular  army  and  national  guard  would  be  6,000  men 
and  332  officers.  A  very  considerable  number  of  the  regular 
officers  would  be  required  in  the  training  of  the  volunteer  ehgi- 
neers,  in  the  control  of  civilian  contractors  and  laborers  in  the 
land  defense  works  of  our  important  cities  and  arsenals  and  works 
on  the  lines  of  communication,  the  direction  of  civilian  surveyors 
in  the  preparation  of  military  maps  of  the  theaters  of  war,  and 
many  other  special  duties.  But  assuming  that  all  were  available 
for  the  tactical  duties  hereinbefore  outlined,  there  remains  a 
deficiency  of  1,200  officers  and  44,000  men. 

History  has  demonstrated  again  and  again  that  efficient  trained 
officers  are  the  most  important  part  of  an  army.  In  the  hands 
of  competent  officers  green  troops  have  been  known  to  give  a 
good  account  of  themselves,  whereas  the  best  troops  have  been* 
uselessly  sacrificed  by  incompetent^leaders.  Napoleon  is  credited 
with  the  statement  that  he  would  rather  have  an  army  of  lambs 
commanded  by  lions  than  an  army  of  lions  commanded  by  lambs. 
These  truths  will  be  almost  self-evident  and  they  are  especially 
applicable  to  engineer  troops  on  account  of  the  variety  of  their 
duties.  To  obtain  trained  officers  is  more  difficult  than  to  obtain 
trained  troops,  since  the  time  and  effort  required  to  fit  officers 
for  the  performance  of  their  duties  is  greater  than  in  the  case  of 
enlisted  men.  The  officers  for  this  engineer  force  are  accordingly 
our  chief  concern. 

An  officer  to  command  engineer  troops  should  have  the  follow- 
ing qualifications: 

It  is  essential  that  he  have  a  good  constitution,  able  to  with- 
stand the  hardships  of  a  campaign.  He  should  be  a  man  of  high 
professional  qualifications,  both  as  a  soldier  and  as  an  engineer. 
Without  such  qualifications  an  engineer  officer  can  not  properly 
plan  nor  execute  the  varied  works  that  will  be  assigned  to  him, 
nor  properly  subordinate  his  work  to  the  needs  of  the  combatant 
forces;  he  can  not  command  the  respect  and  confidence  of  his  own 
men  and  can  not,  consequently,  maintain  discipUne.     He  should 


10  THE  ENGINEER  IN  WAR 

be  zealous  in  the  performance  of  his  duty — which  ordinarily  im- 
plies an  interest  in  his  work,  resourceful,  and  last  but  not  least, 
a  student  of  human  nature,  knowing  how  to  handle  men  so  as 
to  produce  the  best  results  under  trying  circumstances.  Wlience 
and  how,  under  present  conditions,  are  1,200  trained  engineer 
officers  to  be  obtained  in  the  event  of  war? 

It  is  essential  under  our  present  policy  that  we  provide  for  a 
large  reserve  of  at  least  partially  trained  men.  The  object  of 
this  partial  training  is,  of  course,  to  reduce  as  much  as  possible 
the  time  required  for  the  final  training  of  the  volunteer  army  that 
would  be  assembled  at  the  outbreak  of  war.  The  time  required 
to  train  the  ofl&cers  will  be  greater  than  in  the  case  of  the  men  and 
accordingly  special  attention  must  be  devoted  to  the  peace  train- 
ing of  the  men  on  whom  we  must  rely  to  furnish  officers  for  this 
vast  force  of  volunteers.  The  officer  of  engineers  must  be  not 
only  a  trained  and  disciplined  soldier  but  in  addition  a  competent 
and  experienced  engineer.  In  other  words,  he  must  have  train- 
ing along  two  lines  to  fit  him  for  the  discharge  of  his  duties.  It 
is  not  sufficient  that  he  be  instructed  merely  in  the  technical 
details  of  his  work.  He  must  have  his  tactical  sense  so  developed 
as  to  be  able  to  grasp  the  situation  of  the  moment  and  intelli- 
gently bend  his  energies  to  meet  it  with  suitable  works.  This 
means  that  the  volunteer  engineer  officer  could  not  be  brought 
to  the  same  state  of  efficiency  in  his  own  lines  as  quickly  as  the 
volunteer  infantry  officer,  unless  he  had  previous  training  and 
experience  in  civil  engineering.  The  volunteers  taking  the  field 
should  be  trained  to  a  certain  minimum  standard  of  efficiency. 
Otherwise,  efficient  infantry  would  be  severely  handicapped  by 
being  forced  to  depend  upon  inefficient  engineers.  If  this  neces- 
sary condition  is  to  be  realized  it  is  evident  that  we  must  obtain 
our  volunteer  engineer  officers  from  a  class  of  men  having  previous 
training  along  engineering  and  construction  lines.  The  nation 
then  depends  upon  the  engineering  and  contracting  professions 
to  furnish  these  men. 

If  our  volunteer  engineer  officers  are  to  be  fitted  to  take  the 


THE  MILITARY  POLICY  OF  THE  UNITED  STATES        11 

field  on  a  plane  of  equality  with  volunteer  officers  of  the  other 
arms,  special  effort  in  the  way  of  preliminary  training  will  be 
necessary.  Military  engineering  in  a  general  sense  is  the  adap- 
tation of  civil  engineering  to  the  conduct  of  war.  It  is  a  special 
application  of  the  engineering  art,  and  its  methods  and  economics 
are  essentially  different  from  those  which  characterize  good  civil 
practice.  It  is  our  purpose  to  inquire  into  the  relation  of  engi- 
neering to  the  conduct  of  war  and  the  methods  characteristic  of 
mihtary  engineering,  to  the  end  that  the  civil  engineers  and  con- 
tractors of  the  United  States  may  partially  prepare  themselves 
in  advance  for  the  patriotic  duty  which  they  may  be  called  upon 
to  perform. 

There  is  no  science  known  to  mankind,  from  astronomy  to 
bacteriology,  which  does  not  find  its  application  in  the  conduct 
of  war.  There  is  scarcely  a  practitioner  or  artisan  who  may  not 
contribute  his  share  to  the  national  defense.  Even  the  clergy- 
man and  the  musician,  the  exponents  of  peace  on  earth  and  the 
gentlest  of  the  arts,  are  called  upon.  Thus  do  we  obtain  a  prac- 
tical conception  of  the  theory  that  all  the  intellectual  resources 
of  the  nation  should  be  at  the  command  of  the  government  in  the 
prosecution  of  a  war  on  which  the  fate  of  the  nation  may  depend. 
Of  the  peaceful  arts  that  contribute  the  results  of  their  research 
and  practice  to  the  successful  prosecution  of  war,  none  is  of  more 
vital  importance  than  engineering. 


CHAPTER  II 

GENERAL  DUTIES  OF  THE  MILITARY  ENGINEER  AND 
ECONOMICS  OF  MILITARY  ENGINEERING 

The  duty  of  the  mihtary  engineer  in  time  of  war  is  to  plan  and 
execute  all  works  of  an  engineering  nature  which  are  required  in 
connection  with  the  operations  of  the  army.  It  will  be  apparent 
that  this  is  a  wide  field  of  endeavor.  The  engineering  require- 
ments of  an  army  include  most  of  those  of  the  average  large  com- 
munity, and  in  addition  many  others  not  called  for  by  the  gentle 
vocations  of  peace.  The  military  engineer  must  have,  therefore, 
a  thorough  working  knowledge  of  the  more  important  branches 
of  civil,  mechanical  and  electrical  engineering  as  appUed  to  mili- 
tary needs.  This  might  appear  to  be  more  than  an  average  man 
could  be  expected  to  know,  and  so  it  would  be  did  we  demand  of 
the  military  engineer  all  the  precision  and  nicety  characteristic 
of  civil  practice.  Military  engineering,  in  rather  sharp  contrast 
to  good  civil  practice,  is  characterized  by  makeshifts  and  tempo- 
rary expedients.  ''Build  for  posterity,"  says  the  civil  engineer. 
He  places  the  foundations  of  his  bridge  at  great  expense  of  time 
and  labor  on  the  solid  rock  and  he  has  a  just  pride  in  the  enduring 
nature  of  the  structure  he  erects.  In  his  brain  is  the  accumulated 
knowledge  of  centuries  of  painstaking  construction.  Long  after 
his  death  the  great  bridge  remains,  a  monument  to  his  skill  and 
devotion.  How  different  is  the  case  of  the  military  engineer. 
Not  for  posterity  builds  he,  but  for  the  exigency  of  the  moment. 
Not  on  the  solid  rock  does  he  place  his  foundations,  but  often  on 
the  heaving  bosom  of  the  stream  itself.  The  army  arrives  at  the 
impassable  stream  and  the  engineer  rapidly  scans  the  situation. 
In  his  brain  also  is  the  accumulated  knowledge  of  centuries  of 

12 


GENERAL  DUTIES  OF  THE  MILITARY  ENGINEER        13 

scientific  warfare.  Aladdin's  lamp  is  rubbed.  And  lo,  in  the 
twinkling  of  an  eye,  the  wonderful  bridge  is  there  and  the  army 
with  all  its  animals  and  heavy  vehicles  proceeds  across.  To  the 
frail  but  still  adequate  structure  are  committed,  not  only  the 
lives  of  the  troops,  but  the  destinies  of  the  nation  perhaps. 

The  military  engineer  must  possess  not  only  a  thorough 
knowledge  of  construction  but  also  a  thorough  knowledge  of  the 
art  of  warfare.  He  must  foresee  the  needs  of  the  army  and 
build  to  meet  those  needs,  and  on  his  sagacity,  energy,  foresight 
and  resourcefulness  the  issue  of  the  campaign  may  indeed  depend. 

The  duties  of  engineer  troops  in  the  United  States  Army  in 
time  of  war  may,  with  respect  to  location,  be  classified  as  follows: 

1.  At  bases,  mobilization  camps  and  advance  supply  depots. 

2.  On  the  line  of  communications. 

3.  In  the  attack  and  defense  of  fortified  places  (siege  operations). 

4.  With  the  mobile  army  in  the  6eld. 

Each  of  these  is  further  capable  of  subdivision,  and  may  include 
a  great  variety  of  works.  Duty  with  the  mobile  army  is  the  prime 
function  of  engineer  troops,  and  is  the  one  on  which  their  organi- 
zation, training,  and  equipment  should  primarily  be  based.  All 
other  engineering  duties  (except  possibly  siege  operations)  must 
be  regarded  as  special.  They  will,  when  necessary,  be  performed 
by  engineer  troops,  either  regular  or  volunteer,  with  such  changes 
or  additions  in  personnel  or  equipment,  civiUan  assistance,  etc., 
as  the  special  situation  or  exigency  may  demand. 

The  engineer  troops  for  field  service  should  be  with  the  com- 
batant forces  at  the  front,  at  all  times  subject  to  the  immediate 
orders  of  the  commanders  of  the  divisions  or  armies  to  which 
they  may  be  attached.  Their  duties  will  be  intimately  connected 
with  the  movements  and  tactical  operations  of  the  fighting 
forces,  and  should  be  characterized  by  extreme  rapidity,  full 
use  of  local  resources,  and  a  thoroughness  all  sufficient  unto  the 
immediate  needs  and  no  more  than  sufficient.  Subject  to  these 
conditions,  the  operations  of  the  field  engineers  may  be  roughly 
classified  as  follows: 


14  THE  ENGINEER  IN  WAR 

1.  Operations  to  facilitate  the  rapid  movement  of  the  combatant  forces. 

2.  Operations  to  increase  the  offensive  or  defensive  powers  of  the  com- 
batant forces  and  to  limit  or  decrease  those  of  the  enemy. 

3.  Operations  to  maintain  the  health  and  promote  the  comfort  of  the 
troops.     In  brief,  these  duties  may  be  classed  as — 

1.  Transportation. 

2.  Fortification. 

3.  Sanitation. 

In  short,  promoting  and  conserving  the  operating  efficiency 
of  the  troops.  The  works  required  under  these  heads  will  be 
numerous  and  varied  according  to  the  course  of  the  campaign, 
the  nature  of  the  theater  of  operations,  the  season,  the  weather, 
and  other  conditions.  The  most  extended  catalogue  of  such 
works  would  still  be  incomplete,  but  a  statement  somewhat  in 
detail  of  the  more  important  duties  ordinarily  to  be  performed, 
is  necessary  as  a  basis  for  our  discussion. 

It  is  of  the  utmost  importance  in  every  case  to  draw  the  line 
of  demarcation  between  the  duties  of  the  field  engineers  at  the 
front  and  those  which  properly  pertain  to  the  engineer  or  other 
personnel  on  the  lines  of  communication.  This  is  necessary  in 
order  to  insure  smooth  cooperation,  and  the  presence  in  every 
tactical  emergency  of  the  mobile  engineer  troops  with  the  com- 
batant forces.  The  supreme  commander  in  the  field  will  in  each 
case  prescribe  and  limit  the  functions  of  the  two  organizations. 
Those  of  the  field  engineers  should  include  no  work  which  might 
have  been  performed  by  others.  There  will  be  enough  which 
they  alone  can  execute,  and  their  energies  should  not  be  frittered 
away  on  work  for  which  other  special  troops  or  civilians  are  or 
might  be  made  available. 

The  more  important  special  duties  of  engineer  troops  in  the 
mobile  army  may  include: 

1.  Reconnaissance  of  the  natural  and  cultural  features  of  the  terrain,  pre- 
liminary to  tactical  operations,  or  for  other  purposes.  Reconnaissance  of 
hostile  works  and  dispositions. 

2.  Collection  of  maps  and  other  data  from  local  sources. 

3.  Correction  and  amplification  of  existing  charts. 


GENERAL  DUTIES  OF  THE  MILITARY  ENGINEER         15 

4.  Mapping  of  limited  portions  of  the  terrain  within  the  sphere  of  tactical 
operations,  and  other  minor  survey  duties. 

5.  Map  reproduction,  field  methods. 

6.  Collection  and  utilization  of  local  engineering  resources  in  personnel 
and  material. 

7.  Laying  out  of  defensive  positions  and  points  of  support. 

8.  Planning  and  superintendence  of  offensive  or  defensive  field  fortifica- 
tions, including  obstacles,  sapping  and  mining,  etc.,  and  the  execution  of  the 
more  difficult  tasks  in  connection  therewith. 

9.  Laying  out  and  improving  camps. 

10.  Sanitation,  including  water  supply  and  sewage  disposal. 

11.  Construction  and  repair  of  roads,  railroads  and  bridges. 

12.  Construction  of  temporary  buildings,  and  repair  of  permanent 
buildings  and  other  structures. 

13.  Military  demolitions. 

— etc.,  etc. 

Engineer  troops  must  also  be  trained  to  take  their  place  on  the  firing  line 
in  battle,  the  same  as  the  infantry. 

The  ideal  engineer  troops  are  those  prepared  to  execute  all 
tasks  which  nuiy  be  iussigned  them,  and  the  engineers  of  the 
United  States  Army  are  trained  with  this  end  in  view.  In 
the  field  they  must  not  only  meet  but  anticipate  the  needs  of  the 
army.  To  this  end  the  chief  engineer  should  be  at  all  times  in 
close  touch  with  the  commander-in-chief  and  with  the  engineer 
troops,  and  each  battalion  and  company  commander  of  the 
engineers  must  be  at  all  times  in  close  touch  and  hearty  coopera- 
tion with  the  troops  of  the  line  with  whom  he  is  serving. 

On  account  of  the  variety  of  duties  exacted  of  an  army  in  war, 
we  find  a  strong  tendency  in  many  countries  to  specialize  the 
work  of  the  technical  troops.  By  this  is  meant  that  certain 
organizations  are  trained  to  perform  a  certain  kind  of  work  and 
are  not  supposed  to  be  employed  in  anything  outside  of  their 
specialty.  Thus  we  find  in  the  European  armies  sapper  com- 
panies, railroad  companies,  aero  companies,  telegraph  companies, 
etc.  One  foreign  engineer  has  even  recommended  the  organi- 
zation of  water-supply  companies. 

In  our  own  service  the  duties  of  the  foreign  aero  and  telegraph 


16  THE  ENGINEER  IN  WAR 

companies  fall  to  the  Signal  Corps.  All  the  remaining  technical 
field  operations  demanded  by  the  modern  army  are  to  be  per- 
formed by  the  engineers — an  entirely  feasible  arrangement.  If 
we  were  to  have  special  troops  for  each  technical  duty  there  would 
be  no  limit  to  their  numbers.  Moreover,  many  of  these  duties 
are  sporadic  in  their  nature  and  the  troops  trained  to  perform 
them  would  necessarily  be  idle  a  large  part  of  their  time,  or  else, 
which  is  more  probable,  they  would  be  assigned  to  other  duty, 
for  which  they  should  have  been  trained.  So  far  as  our  own 
service  is  concerned,  a  multitude  of  special  troops  would  be  a 
useless  expense,  and  our  engineer  companies  can  and  should  be 
trained  to  perform  satisfactorily  all  the  engineering  operations 
required  by  the  mobile  army,  including  the  mapping  of  limited 
portions  of  the  terrain,  the  construction  of  temporary  buildings, 
water  supply,  the  hasty  repair  of  railroads,  etc.  A  single  organi- 
zation large  enough  to  have  representatives  with  every  command 
from  a  brigade  up  is  thus  always  available  and  quaUfied  to  per- 
form any  task  that  may  be  assigned.  With  special  organizations 
for  each  class  of  work,  the  number  of  each  would  necessarily  be 
relatively  small.  It  would  be  impossible  to  assign  them  to  any 
except  large  commands.  They  would  frequently,  as  a  consequence, 
be  wanting  when  most  needed,  would  be  idle  part  of  the  time  and 
swamped  with  work  during  the  remainder.  It  would  be  better 
to  have  the  necessary  special  workmen  and  plenty  of  "handy 
men"  in  each  company,  with  officers  quaUfied  to  superintend 
and  direct  all  classes  of  technical  work.  Engineering  operations 
with  the  field  army  are  nearly  all  in  the  nature  of  makeshifts. 
They  should  be  sufficient  for  the  immediate  purpose,  and  no  more. 
Extensive  work  of  a  special  nature  (excepting  siege  operations) 
will  generally  be  executed  in  rear  of  the  army,  and  special  pro- 
visions therefor  can  be  made  as  the  occasions  arise. 

The  specialization  which  has  contributed  so  greatly  to  the 
success  of  the  civil  engineering  profession  finds  a  much  more 
limited  application  in  the  military  field.  The  great  variety  of 
duties  exacted  of  the  miUtary  engineer  and  his  frequent  encounters 


GENERAL  DUTIES  OF  THE  MILITARY  ENGINEER         17 

with  emergencies  demand  broad  general  training.  He  should  be 
well  qualified  to  perform  all  these  various  duties  but,  having 
such  quaUfications,  he  may  then  in  addition  specialize  along 
certain  lines.  Such  specialization  should  not  be  pursued  to  the 
injury  of  his  general  efficiency.  He  should  be  well  qualified  for 
all  his  duties  and  his  usefulness  will  be  increased  if  he  has  special 
qualifications  in  certain  lines.  The  ideal  military  engineer  is  the 
'' all-around  man"  who  can  turn  his  hand  to  anything.  On 
such  a  man  the  nation  relies  and  specialists  become  tools  in  his 
hands.  There  will  be  a  large  field  of  usefulness  for  our  engineering 
specialists  in  time  of  war,  but  not  to  any  great  extent  with  the 
mobile  army  in  contact  with  the  enemy.  Even  without  military 
training  or  any  conception  of  the  tactical  or  strategical  require- 
ments of  the  situation,  they  may  be  usefully  employed  on  the 
more  formal  works  in  the  rear  of  the  army  under  the  direction 
of  expert  military  engineers  who  fully  understand  these  require- 
ments and  whose  broad  training  enables  them  to  intelligently 
direct  the  work  of  specialists  of  all  classes.  We  are  here  con- 
cerned, however,  with  officers  for  service  with  the  mobile  engineer 
troops  forming  part  of  the  fighting  forces.  For  all  such,  broad 
engineering  training  and  high  tactical  efficiency  are  essential. 
Their  specialties,  if  such  they  have,  may  or  may  not  find  useful 
application.  But  as  specialists  alone  they  would  here  be  of 
httle  value  and  unable  to  meet  the  emergencies  which  will  con- 
stantly confront  them. 

Military  engineering,  as  we  have  seen,  is  an  adaptation  of 
civil  engineering  to  military  needs.  The  fundamental  difference 
between  the  two  arts  is  in  their  economic  aspects.  Military 
engineering,  no  less  than  civil  engineering,  is  an  economic  art, 
but  the  standards  by  which  it  is  judged  are  quite  different.  In 
civil  engineering  the  element  of  first  cost  is  of  prime  importance. 
The  matter  of  time  consumed  in  construction  is  of  importance 
as  a  rule  only  as  affecting  the  first  cost  and  the  financial  returns 
on  the  investment.  A  considerable  time  spent  in  design  and 
other  preliminaries  to  construction  will  usually  be  amply  justified 


18  THE  ENGINEER  IN  WAR 

by  a  material  saving  in  first  cost.  The  Board  of  Directors  insists 
that  the  engineer  hold  down  the  first  cost.  Also  the  structures 
of  the  civil  engineer  are  usually  rather  permanent  in  their  nature. 
Generally  they  are  intended  to  endure  for  years,  often  they  are 
made  as  permanent  as  possible  on  the  ground  that  their  greater 
usefulness  and  lower  cost  of  maintenance  will  eventually  justify 
the  increased  first  cost.  Such  are  the  economics  of  civil  en- 
gineering. Those  of  military  field  engineering  are  very  different. 
In  order  to  appreciate  this  we  must  first  consider  the  economic 
aspect  of  warfare.  The  cost  of  modern  war  between  two  great 
nations  is  enormous.^  The  belligerent  government  pays  immense 
liquidated  damages  for  every  day  that  the  duration  of  the  con- 
flict is  protracted.  The  cost  of  success  is  great  enough — that  of 
failure  is  usually  much  greater.  A  few  days — even  a  few  hours — 
have  decided  the  issue  of  a  battle  and  the  fate  of  a  nation.  Ac- 
cordingly the  march  of  events  is  rapid  in  modern  warfare. 
Everything  must  move  with  the  utmost  celerity.  Thus,  time  is 
the  controlling  element.  The  commanding  general  does  not  ask 
his  engineer  ''How  much  will  it  cost?"  but  "How  soon  will  it  be 
ready?"  Also  the  structures  of  military  field  engineering  are 
essentially  impermanent  in  their  nature.  Often  they  are  required 
only  for  the  exigency  of  the  moment — never  are  they  needed 
beyond  the  close  of  hostilities.  Thus  they  are  all  in  the  nature 
of  makeshifts.  In  sharp  contrast  to  civil  practice  we  find  that 
any  cost  will  be  justified  if  it  results  in  a  saving  of  time  at  a 
critical  juncture.  The  military  engineer  plays  for  big  stakes. 
He  makes  a  fatal  blunder  and  shows  his  utter  lack  of  appreciation 
of  the  economics  of  warfare  if  he  hesitates  over  details  involving 
thousands  of  dollars  while  the  fate  of  a  nation  trembles  in  the 
balance. 

As  a  consequence  of  these  conditions,  works  of  military  engi- 
neering will  usually  be  conducted  with  feverish  rapidity.     The 

*  The  direct  cost  of  the  present  European  war  to  all  the  belligerents  has 
been  estimated  at  about  $100,000,000  per  day,  not  including  incidental 
losses  to  industry  and  commerce. 


GENERAL  DUTIES  OF  THE  MILITARY  ENGINEER         19 

best  pioneer  is  the  one  who  produces  results  just  sufficient  for 
the  immediate  purpose  in  the  minimum  of  time  without  regard 
to  expense.  Formal  and  finished  works  will  be  left  to  those  in 
the  rear.  The  pioneer  with  the  mobile  army  eagerly  seeking  a 
tactical  decision  has  no  time  for  niceties.  Their  presence  in  his 
work  is  almost  certain  indication  of  criminal  incompetence — lack 
of  appreciation  of  economic  principles.  A  trail  ferry  which  gets 
the  troops  across  in  time  is  better  than  a  memorial  bridge  which 
does  not.  The  rough-and-ready  makeshifts  which  serve  their 
purpose  are  the  triumphs  of  the  military  engineer's  art.  They 
have  the  beauty  of  utilitarianism. 

To  be  qualified  then  to  meet  the  heavy  responsibilities  that  will 
1)(^  placed  upon  him,  the  military  engineer,  even  more  than  his 
( ivilian  confrere,  must  be  a  keen  student  of  economics  as  appUc- 
able  to  warfare.  He  must  be  intimately  familiar  with  the  struc- 
tural needs  of  military  works  and  with  the  details  of  design, 
adaptation  to  available  resources,  and  methods  of  construction 
which  promote  speed.  But  this  alone  is  not  sufficient.  Works 
of  military  engineering  are  utilized  to  meet  the  tactical  needs  of 
the  moment.  If  constructed  without  due  regard  to  the  tactical 
situation  they  may  be  worse  than  useless.  The  fleeting  oppor- 
tunities to  snatch  victory  or  evade  defeat  must  be  seized  as  they 
present  themselves.  They  must  even  be  foreseen,  for  once  gone 
they  may  never  again  be  presented.  To  grasp  these  opportuni- 
ties and  meet  the  ever-changing  needs  the  engineer  must  be  not 
only  skilled  in  construction  but  possessed  also  of  tactical  sense 
and  training.  His  errors  in  judgment,  his  lost  opportunities  are 
paid  for,  not  in  money  alone,  but  in  national  prestige  and  pros- 
perity and  in  blood. 

A  simple  example  in  the  nature  of  a  parallel  may  serve  to  illus- 
trate the  difference  in  the  economics  of  peace  and  those  of  war. 
At  a  certain  locaUty  a  bridge  is  needed  over  a  stream.  While  it 
is  very  desirable,  the  community  can  wait  several  months,  if 
necessary.  Their  resources  are  limited — they  can  afford  to  pay  so 
much  and  no  more.     The  civil  engineer  charged  with  the  con- 


20  THE  ENGINEER  IN  WAR 

struction  of  the  bridge  makes  a  careful  study  of  the  needs  of  the 
situation.  Eventually  he  designs  an  excellent  structure,  ample 
in  strength  and  capacity  and  durable  in  its  nature,  and  his  esti- 
mate is  within  the  stipulated  price.  The  work  is  advertised  for 
contract,  but  all  bids  are  rejected  as  being  excessive.  Eventually 
the  bridge  is  erected  by  day  labor.  This  results  in  a  considerable 
delay  but  keeps  down  the  cost.  The  community  believes  that 
the  engineer  has  well  discharged  the  duty  placed  upon  him. 
They  consider  that  the  delay  is  compensated  by  the  saving  in 
cost. 

It  is  war  time  and  an  army  approaches  the  same  stream.  Its 
mission  is  to  cross  the  stream  and  seize  an  important  position  on 
the  other  side  before  the  enemy  can  reach  and  hold  it.  The 
engineer  with  this  force  is  called  upon  for  a  bridge  to  replace  the 
one  that  has  been  unexpectedly  destroyed.  ''It  must  be  ready 
by  day  after  tomorrow,"  the  Commanding  General  informs  him, 
"or  my  opportunity  will  be  lost."  Unlike  the  civil  community 
the  army  cannot  wait  for  its  bridge.  The  engineer  finds  that  no 
suitable  lumber  is  at  hand.  But  he  perceives  a  number  of  costly 
buildings  whose  demolition  will  furnish  what  he  needs.  The 
owners  protest  their  destruction.  The  engineer  is  well  aware 
that  they  will  place  claims  for  many  thousands  of  dollars  against 
the  government.  But  he  realizes  the  vital  need  for  the  bridge 
and  rightly  considers  the  cost  as  insignificant  by  comparison. 
He  is  not  restricted  to  the  available  funds  of  a  small  community, 
but  has  at  his  command  the  vast  resources  of  a  great  and  wealthy 
nation.  The  buildings  are  demolished  in  spite  of  protest  and  the 
bridge  is  built.  It  is  not  a  sightly  nor  durable  structure  and  its 
cost  proves  to  be  far  in  excess  of  that  of  the  splendid  bridge  built 
by  the  civilian  engineer.  But  it  is  there  on  time  and  it  serves  its 
purpose.  The  army  accomplishes  its  mission,  which  proves  to 
be  a  contributing  cause  of  ultimate  victory.  The  damage  claims 
are  presented  and  cheerfully  paid  in  full.  The  nation  believes 
that  the  engineer  has  well  discharged  the  duty  placed  upon  him. 


I 


GENERAL  DUTIES  OF  THE  MILITARY  ENGINEER        21 


They  consider  that  the  excessive  cost  of  the  bridge  is  amply 
compensated  by  the  saving  of  time  at  a  critical  juncture. 

How  different  are  the  methods  of  the  two  engineers !  Yet  each 
met  correctly  the  demands  of  the  situation  which  confronted  him. 

The  two  chief  essentials  of  military  field  engineering  then,  are: 

1.  The  adaptation  of  engineering  work  to  tactical  needs. 

2.  Appreciation  of  the  economics  of  warfare,  which  ordinarily  demands 
high  speed  in  construction,  even  at  a  sacrifice  of  money  and  life. 

We  have  seen  the  very  wide  range  of  operations  which  may  be 
icquired  of  the  miUtary  engineer.  That  the  average  man  should 
l)ossess  a  civilian  specialist's  knowledge  of  all  these  matters  is 
beyond  the  bounds  of  possibihty.  This,  however,  is  neither  nec- 
essary nor  desirable.  The  pioneer  operations  with  the  mobile 
army  are  all  in  the  nature  of  makeshifts  or  improvisations,  char- 
acterized by  the  utmost  simplicity.  Only  the  simplest  works 
can  be  successfully  executed  in  the  haste  and  excitement  attend- 
iit  upon  field  operations.  Nicety,  finish,  refinement  and  per- 
manency are  deliberately  avoided.  In  the  words  of  one  of  our 
most  distinguished  military  engineers — "Simplicity  must  be  the 
watchword  in  plans  of  operation,  in  orders,  in  action,  and  in 
equipment.  Directness  can  be  secured  only  when  simplicity  per- 
vades the  whole  machine."  Simplicity  is  demanded  by  the  re- 
quirement of  rapidity  in  construction,  by  the  absence  of  skilled 
labor,  and  by  the  lack  of  facilities,  such  as  suitable  supplies  and 
materials,  machinery  and  appliances.  Skilled  labor,  special 
materials  and  suitable  construction  plant  will  indeed  be  utilized 
whenever  it  is  practicable  to  do  so,  and  opportunities  for  their 
successful  employment  should  never  be  neglected.  Neverthe- 
less, in  the  fore-front  of  operations,  often  in  the  presence  of  the 
enemy,  even  actually  under  his  fire,  construction  can  and  must 
be  carried  on  under  conditions  which  would  be  exceedingly  dis- 
couraging to  the  average  civilian  engineer  or  contractor.  It  is 
the  simplest  works,  comparatively  few  in  number,  which  will 
most  frequently  be  demanded.  It  is  for  the  execution  of  these 
simple  works  that  engineer  officers  and  troops  should  primarily  be 


22  THE  ENGINEER  IN  WAR 

trained.  The  officers  should  also,  by  study  and  observation, 
endeavor  to  fit  themselves  to  meet  the  special  requirements  of 
the  less  usual  situations  which  will  occasionally  be  presented. 

The  methods  by  which  speed  in  construction  may  be  attained 
are  so  numerous  and  varied  that  a  thorough  discussion  of  them 
would  fill  many  volumes.  They  constitute  a  study  which  no 
engineer,  military  or  civilian,  can  afford  to  neglect.  The  sug- 
gestions which  follow  are  applicable  to  military  operations  but 
will  not  be  new  to  the  civil  engineering  profession. 

The  average  contractor  has  an  incentive  to  rapid  work  in  the 
increased  financial  returns  it  usually  brings.  The  mihtary  engi- 
neer lacks  this  incentive,  but  must  be  actuated  instead  by  an 
unselfish  patriotic  devotion  to  duty  and  by  a  common  incentive 
of  the  salaried  professional  man — a  selfish  but  commendable 
desire  to  excel  in  his  particular  line  of  work  and  enjoy  a  reputa- 
tion for  efficiency. 

When  confronted  with  a  situation  the  military  pioneer  seeks 
not  the  best  permanent  solution  but  the  easiest  and  quickest 
makeshift  which  will  serve  the  purpose  in  view.  He  does  not 
construct  a  new  bridge  if  an  existing  bridge  can  be  adapted  to 
his  needs,  nor  if  a  practicable  ford  can  be  found. 

Formal  plans  are  rarely  used,  ordinarily  nothing  more  than 
simple  sketches  is  required.  These  consist  of  an  instantaneous 
adaptation  of  military  type  plans  to  the  materials,  tools  and  labor 
available.  All  details  which  increase  the  time  required  for  con- 
struction without  being  absolutely  essential  to  the  completed 
structure  are  eliminated  and  the  remaining  details  reduced  to  the 
simplest  form.  Unless  construction  plant  is  available,  which 
will  seldom  be  the  case,  very  large  pieces  should  be  avoided.  All 
pieces  should  be  of  such  size  that  they  can  be  readily  obtained 
and  easily  handled  by  the  men  with  the  assistance  of  animals 
and  simple  tackle. 

It  is  not  to  be  supposed  indeed  that  all  military  field  engineering 
is  in  the  nature  of  sudden  emergencies.  Frequently  the  need  of 
certain  structures  can  be  foreseen  days  or  weeks  in  advance,  and 


GENERAL  DUTIES  OF  THE  MILITARY  ENGINEER        23 

when  this  is  the  case,  careful  and  elaborate  preliminary  arrange- 
ments may  be  possible. 

In  starting  work  the  necessary  tools  are  laid  out,  and  steps 
taken  in  advance  to  have  all  necessary  material  on  hand  as  soon 
as  it  may  be  required.  The  work  should  then  be  divided  into 
a  number  of  definite  tasks  under  the  officers  and  senior  non-com- 
missioned officers,  and  these  again  subdivided  into  smaller  tasks, 
under  the  junior  non-commissioned  officers.  The  cost  of  super- 
intendence, which  might  be  prohibitive  on  civil  work,  is  justified 
in  military  construction  if  it  results  in  a  saving  of  time.  If  sev- 
eral of  the  tasks  can  be  made  similar  in  nature  and  equal  in 
amount,  so  much  the  better.  This  will  create  competition,  al- 
ways a  stinmlus  to  endeavor.  Two  identical  structures  with  an 
equal  number  of  men  assigned  to  each  will  usually  call  forth  the 
l)est  efforts  of  both  parties.  Of  course,  that  task  which  will 
require  longest  to  accomplish  should  be  started  first  and  pushed 
hardest,  if  the  time  required  for  its  completion  is  the  measure  of 
the  time  required  for  the  work  as  a  whole.  The  number  of  men 
assigned  to  any  task  should,  as  a  rule,  be  the  minimum  that  can 
properly  execute  it.  Too  many  men  on  a  task  are  always  a  cause 
of  confusion  and  delay.  If  there  be  a  superfluity  of  men  it  is 
better  to  put  them  on  some  other  work  or  send  them  away  than 
to  have  them  standing  idle.  Extra  men,  if  kept  on  hand,  can 
be  best  utiUzed  in — 

(a)  Collecting  and  preparing  materials,  or 

(6)  Relieving  the  men  engaged  in  the  more  arduous  tasks. 
It  should  never  be  necessary  to  have  any  men  idle,  except  when 
they  are  actually  resting.  There  always  will  be  tasks  in  con- 
nection with  any  piece  of  work,  the  performance  of  which  will  not 
tire  the  men  as  much  as  standing  around,  which  is  very  fatiguing. 
Extra  non-commissioned  officers  should  be  put  to  work,  on  the 
more  dignified  tasks,  of  course.  They  should  not  be  allowed  to 
entertain  the  idea  that  their  sole  function  is  to  superintend.  The 
senior  non-commissioned  officers  should  not  scruple  to  lend  a 
hand  when  necessary,  or  to  show  some  man  who  is  bungling  his 


24  THE  ENGINEER  IN  WAR 

work  the  proper  method.  But  they  should  not,  in  so  doing, 
neglect  the  more  important  work  of  superintendence.  The  cap- 
tain or  officer  in  supreme  charge  should  watch  the  work  as  a 
whole,  generally  leaving  details  to  his  subordinates.  The  fore- 
man of  any  particular  task  should,  when  practicable,  be  given  a 
specific  time  in  which  to  complete  it,  usually  the  least  time  in 
which  the  task  can  possibly  be  accomplished.  While  he  may 
fail  to  complete  it  on  time,  he  will  naturally  be  anxious  to  avoid 
the  explanations  that  will  then  be  demanded  of  him.  If  no  time 
is  set  for  completion,  idling  is  very  apt  to  result.  Two  gangs 
mutually  dependent  upon  each  other,  as  where  one  furnishes  the 
material  which  another  incorporates  in  the  structure,  should  be 
so  organized  that  each  will  be  hard  pushed  to  keep  up  with  the 
other.  This  is  in  the  nature  of  competition.  If  the  number  of 
tools  is  limited,  care  should  be  taken  that  all  tools  are  doing 
useful  work  all  the  time. 


CHAPTER  III 

TOOLS    AND    EQUIPMENT    EMPLOYED    IN    MILITARY 
ENGINEERING 

It  has  frequently  been  remarked  that  military  engineers  make 
very  little  use  of  construction  plant  in  their  field  operations  and 
they  have  been  criticised  for  not  availing  themselves  thereof  to 
a  greater  extent.  Plant  is  utilized  in  military  construction  when- 
ever practicable,  but  in  operations  with  the  mobile  troops  at  the 
front  the  opportunities  for  its  useful  employment  are  decidedly 
limited  in  number.  Such  plant  is,  of  course,  less  useful  on  light 
hasty  military  structures  than  on  the  heavier  and  more  formal 
works  of  peace.  The  work  of  the  military  engineers  is  spread 
over  a  considerable  area,  they  move  rapidly  from  place  to  place, 
and  they  must  at  all  times  keep  up  with  the  mobile  fighting  forces. 
Heavy  construction  plant  is  not  sufficiently  mobile  to  meet  such 
requirements.  Often  it  would  not  be  on  hand  when  needed. 
One  of  the  chief  purposes  of  such  plant  is  to  save  manual  labor, 
and  of  this  there  is  seldom  a  dearth  in  military  operations.  The 
military  pioneer  is  greatly  concerned  in  preserving  his  mobility 
and  accordingly  must  not  be  unduly  hampered  in  his  movements 
by  the  necessity  for  transporting  heavy  machines.  This  is 
(specially  true  in  America  on  account  of  the  deficiency  in  good 
roads.  Therefore  the  engineer  places  his  chief  reliance  on  the 
most  mobile  and  adaptable  of  all  machines^man  himself. 

In  the  occupation  of  a  defensive  position,  each  soldier  in- 
trenches his  own  section  of  the  line.  It  is  quite  apparent  that 
the  troops  can  be  disposed  in  the  position  and  can  complete  the 
excavation,  each  man  using  his  own  portable  tool,  in  a  few  hours 
of  time.  In  such  a  situation,  trenching  machines  could  not 
compete  with  manual  labor.  If  concrete  be  employed  in  such 
intrenchments,  it  would  be  distributed  in  small  masses  over  a 

25 


26  THE  ENGINEER  IN  WAR 

considerable  distance.  Neither  large  nor  small  machine  mixers 
would  be  as  rapid  and  efficient  as  hand  mixing.  The  case  is 
somewhat  similar  to  the  construction  of  concrete  sidewalk.  The 
contractor  constructing  a  block  of  such  sidewalk  economizes 
on  labor  and  employs  a  small  mixing  plant.  But  were  it  neces- 
sary to  lay  such  sidewalk  throughout  the  city  in  a  few  hours  the 
only  practicable  means  of  accomphshing  such  a  task  would  be 
the  employment  of  an  army  of  laborers  and  hand  mixing.  The 
cost  would  be  great  from  the  civil  contractor's  point  of  view, 
but  in  miUtary  operations  the  element  of  time  usually  outweighs 
that  of  cost.  The  men  are  present  and  must  be  paid  and  main- 
tained in  any  case  and,  incidentally,  it  is  in  the  interests  of  dis- 
cipline to  keep  them  employed. 

These  examples  might  be  multiplied  but  those  given  may  be 
regarded  as  typical.  They  indicate  that  the  economics  of 
military  field  engineering  in  general  preclude  any  extensive  em- 
ployment of  heavy  construction  plant.  For  the  more  formal 
work  in  rear  of  the  fighting  forces,  conditions  will  be  different 
and  plant  may  be  more  frequently  employed.  Such  works 
would  include  roads,  railroads  and  bridges  on  the  lines  of  com- 
munication, buildings  at  supply  depots,  the  preparation  of 
secondary  lines  of  defense,  the  rather  dehberate  fortification  of 
important  cities,  arsenals,  supply  depots,  etc.  Here  labor  will 
be  less  plentiful  than  at  the  front,  more  time  will  be  available, 
and  structures  of  a  somewhat  more  permanent  nature  will  \)v 
appropriate.  The  intrenchments  of  the  field  army  are  often 
quite  elaborate,  but  they  are  in  general  located  and  prepared 
in  haste  and  are  later  extended,  improved  and  developed  to  meet 
the  tactical  needs  of  the  situation. 

The  foregoing  considerations  will  also  make  evident  the 
economic  necessity  for  utilizing  to  the  greatest  possible  extent 
the  construction  materials  which  are  available  at  the  site.  The 
necessity  of  bringing  materials  from  a  great  distance  would 
often  cause  most  injurious  delays.  Accordingly,  earth,  timber, 
brush,  gravel,  etc.,  will  be  the  favorite  materials,  and  works 


i 


TOOLS  AND  EQUIPMENT  EMPLOYED 


27 


French 

Intrenching 

Shovel 


U.S.  Intrenching 
Shovel 


i^Pwlftwi^wyRij^dWwq 


U.S.  Intrenching 
Pick 


U.S.  Pioneer 
Pack  Shovel 


Fig.  1. — Portable  tools  employed  in  field  fortification. 


28  THE  ENGINEER  IN  WAR 

should  be  designed  to  utilize  these  as  far  as  possible.  Accessory 
materials  of  construction  which  must  be  transported  to  the  site 
should  be  of  a  portable  nature.  Chief  amongst  these  will  be 
cordage,  nails,  spikes,  wire,  barbed  wire,  etc. 

The  principal  construction  work  of  the  combatant  troops  will 
be  field  fortification.  For  this  work  the  troops  are  supplied  with 
special  miniature  shovels,  pick  mattocks,  saws  and  hatchets, 
which  are  carried  on  their  persons  (Fig.  1).  More  efficient 
work  could,  of  course,  be  performed  with  the  commercial  types 
of  tools.  But  these  must  be  carried  in  wagons  or  motor  trucks 
and  often  would  be  missing  when  most  needed.  *'The  soldier," 
said  Napoleon,  **  should  never  be  separated  from  his  rifle  or  his 
intrenching  tool."  What  was  true  in  Napoleon's  day  is  more 
true  in  this  day  of  trench  warfare.  The  operations  of  the  engi- 
neers being  more  varied,  they  require  a  more  elaborate  equip- 
ment. But  it  must  never  be  forgotten  that  mobihty  is  a  prime 
requisite  and  neither  the  infantry  nor  engineers  should  be 
hampered  in  their  movements  by  the  transportation  require- 
ments of  an  unnecessarily  elaborate  equipment.  The  engineers 
then  will  carry  such  tools  and  materials  as  will  facilitate  their 
operations  without  unduly  restricting  their  mobility.  The 
duties  of  the  engineers  are  so  numerous  that  to  attempt  to  pro- 
vide an  equipment  to  cover  all  contingencies  would  destroy  their 
mobihty,  without  which  any  equipment  would,  of  course,  be 
useless  for  operations  with  the  mobile  army.  An  equipment 
provided  for  service  in  Virginia  would  be  unsuited  for  the  Philip- 
pine Islands,  and  one  provided  for  duty  in  the  field  would  not 
be  entirely  suitable  for  siege  operations.  The  work  of  the 
engineers  in  the  field,  while  varied,  is  all  of  a  rough-and-ready 
order,  and  simple  in  its  nature.  For  the  performance  of  this 
work  an  ample  number  of  the  simple  tools  should  be  provided. 
For  example,  an  adze  is  a  most  useful  tool  in  the  hands  of  a  man 
who  understands  it.  But  it  can  not  do  much  which  might  not 
have  been  accomphshed  with  an  axe;  whereas  the  axe  is  capable 
of  much  for  which  an  adze  is  useless.     Hence,  for  pioneer  opera- 


TOOLS  AND  EQUIPMENT  EMPLOYED  29 


L............ 

^occasionally  be  a  call  for  an  adze,  so  there  should  be  a  few  of 

W  them  in  the  company  equipment. 

'  *  While  the  proper  outfit  for  a  company  would  never  be  the 
same  in  any  two  situations,  nevertheless  it  is  possible  in  a  general 
way  to  decide  upon  the  types  and  numbers  of  the  more  important 
tools.  Lists  of  such  tools  would  constitute  the  "paper  equip- 
ment." A  sufficient  number  should  be  issued  to  the  troops  for 
their  training  in  time  of  peace,  and  a  reserve  should  be  kept 
on  hand  in  a  depot,  sufficient  at  least  to  equip  the  first  troops 
to  take  the  field  in  case  of  war. 

The  tools  and  equipment  of  the  engineers  may  be  divided  into 

'      two  classes,  viz. : 

(a)  Commercial  types  of  tools  and  materials. 

(6)  Special  tools,  apparatus  and  equipment  used  only  by  the 

j      army.  , 

w     Under  (a)  would  be  included  the  great  bulk  of  engineer  equip- 

'■  ment,  not  including  the  ponton  material.  Under  (6)  would  be 
included  such  equipment  as  can  not  be  readily  obtained  on  short 
notice  in  the  commercial  markets;  e.g.,  ponton  material,  the 
miniature  intrenching  tools  issued  to  the  infantry,  tools  for 
military  mining  and  other  siege  material,  wagon  and  pack  equip- 
ment (army  standard),  portable  map  reproduction  outfits,  etc., 
etc.  An  ample  reserve  of  the  second  class  (6)  should  be  kept 
on  hand  at  all  times,  as  there  would  be  a  considerable  delay  in 
obtaining  this  in  sufficient  quantity  on  short  notice,  in  the  event 
of  war,  on  account  of  its  "special"  nature.  An  additional  source 
of  supply,  besides  arsenals  and  home  markets,  is  the  immediate 
theater  of  war,  whose  resources  should  be  utilized  to  the  fullest 
possible  extent.  In  a  thickly  settled  civilized  country  great 
quantities  of  supplies  would  be  locally  available.  In  a  thinly 
settled  or  uncivilized  country  it  would  usually  be  unwise  to 
count  on  anything  except  the  materials  of  nature. 

In  equipping  engineer  troops  to  take  the  field,  the  chief  engi- 
neer officer  of  the  army  will  consider  the  probable  nature  of  the 


30  THE  ENGINEER  IN  WAR 

operations  and  course  of  the  campaign,  the  local  theater  and  its 
resources.  He  would  then  consult  the  list  of  tools  and  equip- 
ment available  at  the  home  depots  or  bases  of  supply,  and  select 
such  as  seemed  best  calculated  to  meet  the  most  probable  needs. 
Possible  needs  should  be  provided  for  by  having  tools  on  hand 
at  the  base  or  at  more  advanced  points,  so  that  they  can  readily 
be  forwarded  when  needed.  The  weight  and  volume  of  the 
equipment  should  be  such  that  t  can  be  carried  in  the  regular 
authorized  wagons  or  motor  trucks  of  the  engineers.  It  should 
include  only  such  material  (as  distinguished  from  tools),  the 
need  for  which  can  be  foreseen,  as  there  is  no  reasonable  hope 
of  obtaining  in  sufficient  quantity  in  the  theater  of  operations. 
It  is  to  be  remarked  that  it  will  usually  be  better  to  over-equip 
rather  than  under-equip  the  engineer  troops  at  the  opening  of 
the  campaign.  Any  excess  of  equipment  over  the  immediate 
needs  can  always  be  left  behind  on  the  lines  of  communications, 
and  brought  up  again  when  required.  Additional  supplies 
which  may  be  required  as  the  campaign  progresses  can  be  sent 
up  as  needed. 

Tools  for  pioneer  work,  like  the  structures  built  herewith, 
should  be  of  the  simplest  character.  A  man  trained  to  their 
use  can  do  excellent  work  with  the  simplest  tools.  The  standard 
pioneer  tools  and  supplies  of  the  engineers  should  include  picks, 
mattocks,  crow-bars,  axes,  adzes,  shovels  (mostly  D  hdl.,  r.p.), 
hammers  (asstd.),  niachetes,  hatchets,  saws,  two-man  saws, 
wire  cutters  and  pliers,  a  few  light  jacks,  augers  (large  sizes), 
a  few  short  rock  drills,  canthooks  or^avies^  pulley  blocks  (up 
to  four  sheaves),  a  couple  of  small  chain  blocks,  lanterns,  marUne, 
rope  for  lashing  and  tackle  (%  in.  suitable  size  for  lashing,  ^  in. 
to  1  in.  suitable  for  tackle,  nothing  larger),  wire  (10  to  14  AWG 
— a  copious  supply),  spikes  and  nails,  various  sizes;  flat  and  round 
iron  for  straps,  bolts,  driftbolts,  dogs,  etc.,  a  little  tool  steel, 
some  tapped  nuts  of  same  sizes  as  round  iron,  and  washers 
(wrought),  machine  and  black  oil  and  oil  for  lanterns,  one  or 
two  light  portable  forges  and  anvils  with  a  Uttle  coal,  a  couple 


TOOLS  AND  EQUIPMENT  EMPLOYED  31 

of  grindstones,  leather,  etc.,  etc.  In  addition  to  these  general 
tools  and  supplies,  there  should  be  several  small  and  compact 
carpenter  outfits,  a  simple  blacksmith's,  machinist's  and  horse- 
shoeing outfits,  a  farrier's  kit,  saddler's  and  shoemaker's  equip- 
ments, sketching  instruments  (to  be  carried  on  persons  of 
sketchers),  a  couple  of  light  transits  (to  be  used  also  as  levels), 
>tadia  rods  (used  also  as  level  rods),  a  number  of  metallic  tapes, 
50  and  100  ft.;  a  simple  plumbing  kit,  twine,  tracing  tape  (for 
laying  out  intrenchments),  a  demoUtion  outfit  (40  per  cent, 
dynamite  is  the  handiest  explosive),  a  camera  and  simple  photo- 
graphic supplies,  a  simple  drafting  and  map  reproduction  out- 
fit, a  field  desk  and  portable  typewriter  for  the  company  office, 
(>tc.  The  entire  equipment  is  ordinarily  carried  in  wagons 
divided  into  compartments  to  permit  ready  accessibihty.  It 
should  however  be  such  that  it  can  be  carried  on  pack  mules, 
in  which  case  survey  instruments,  photo  equipment  and  the 
smaller  and  more  delicate  tools  such  as  carpenter's  outfits  are 
packed  in  boxes  of  a  suitable  size.  Each  company  of  engineers 
ordinarily  includes  a  section  of  mounted  men  and  a  small  pack 
train  carrying  their  equipment.  In  very  rough  country,  where 
wagon  transportation  is  impracticable,  the  entire  equipment 
would  be  carried  on  pack  mules.  There  should  be  an  ample 
supply  of  the  more  common  tools  (especially  picks,  axes,  mat- 
tocks and  shovels)  so  that  when  occasion  arises  the  labor  of  other 
troops  or  of  civilians  can  be  utilized. 

Most  of  the  tools  and  materials  listed  above  should  be  carried 
i)y  each  company  of  engineers,  but  some  of  them  will  be  needed 
only  with  battaUon  headquarters,  such  as  surveying  equipment, 
lithographic  outfits  for  map  reproduction,  etc. 

With  this  simple  equipment  the  engineers  can  perform  all 
the  operations  which  will  ordinarily  be  required  of  them  utiHzing 
such  materials  as  may  be  found  at  hand. 

Beyond  this  it  does  not  seem  advisable  to  recommend  any 
standard  equipment,  except  the  regular  ponton-bridge  equipage. 
There  is  a  large  number  of  special  tasks  for  which  special  equip- 


32  THE  ENGINEER  IN  WAR 

ment  may  be  used  to  advantage.  Such  equipment  should  be 
obtained  locally  or  sent  forward  from  the  base  as  it  is  needed. 
Some  of  it  may  be  taken  with  the  company,  or  in  the  division 
train  if  transportation  is  available  and  the  need  can  be  foreseen. 
Plows  and  scrapers  are  most  useful  for  road  work,  intrenching, 
and  many  other  tasks.  In  a  civiUzed  country  they  can  be 
obtained  in  almost  any  locaHty.  For  extensive  railroad  work 
the  necessary  special  tools  must,  of  course,  be  provided.  They 
will  generally  be  found  wherever  there  is  a  railroad.  For  simple 
railroad  repairs  a  few  claw  and  tamping  bars,  track  jacks,  spik- 
ing hammers,  wrenches,  hack-saws,  track  drills  and  a  "jim- 
crow"  rail  bender  will  be  sufficient.  Traction  and  hoisting  en- 
gines and  the  commercial  t^'pes  of  .trenching  machines  may  be 
used  to  advantage  in  fortification  work  and  almost  any  heavy 
construction.  They  can  not,  of  course,  accompany  the  engi- 
neers in  their  more  rapid  movements,  but  for  elaborate  works 
in  one  locality  they  may  be  sent  forward  when  needed. 

The  battalion  headquarters  may  carry  some  equipment  in 
addition  to  that  of  the  companies.  Extensive  survey  work  and 
map  reproduction  should  preferably  be  under  the  immediate 
charge  of  the  battalion  commander;  the  equipment  therefor, 
especially  Uthographic  (zincographic)  outfits  being  with  battahon 
headquarters,  operated  by  special  skilled  men. 

For  rapid  communication  between  the  separated  portions  of 
an  engineer  command,  engaged  in  section  work  at  various  locali- 
ties, a  small  micro-telephone  outfit  and  a  few  bicycles  should 
form  part  of  the  company  equipment.  All  engineer  officers 
should  be  mounted. 

The  development  of  the  motor  truck  will  greatly  increase  the 
efficiency  of  engineer  troops,  making  possible  the  more  rapid 
transportation  of  tools  and  materials.  It  has  also  made  possible 
the  transportation  of  small,  compact  gasoline  power  plants, 
which  may  have  a  wide  field  of  usefulness.  Up  to  the  present 
time  few  such  plants  have  been  developed,  inasmuch  as  the 
present  war  is  the  first  in  which  the  automobile  has  been  ex- 


TOOLS  AND  EQUIPMENT  EMPLOYED  33 

tensively  employed.  Amongst  the  possible  gasoline  power 
plants  for  military  purposes  are  the  following:  Portable  search- 
lights, winches,  hoists,  pile  drivers,  drills  and  boring  machines, 
saws,  trenching  and  mining  apparatus,  concrete  mixers,  stone 
crushers,  etc.  Very  httle  has  been  done  along  these  Hnes  and 
there  is  room  for  great  improvement. 

Mihtary  field  engineering,  as  we  have  seen,  is  an  adaptation  of 
civil  engineering  and,  in  practice,  differs  from  the  latter  insofar 
as  it  is  governed  by  different  economic  principles  and  conducted 
under  different  conditions.  Fortification  works  executed  in 
time  of  peace  are  essentially  similar  to  civil  engineering  construc- 
tion, and  the  same  is  true  of  many  engineering  operations  con- 
ducted in  time  of  war  on  the  lines  of  communication  in  rear  of 
the  fighting  forces.  On  such  works,  civihan  engineers  without 
military  training  may  often  be  employed  to  advantage.  We 
are  now  concerned,  however,  with  field  engineering,  the  pioneer 
operations  of  the  fighting  forces.  Here  we  find  a  sharp  contrast 
with  civil  practice.  The  conditions  which  govern  the  mihtary 
pioneer  may  be  recapitulated  as  follows : 

1.  All  works  must  be  designed  and  executed  to  meet  actual  tactical  needs. 
If  constructed  without  due  regard  to  the  tactical  situation  they  may  be 
worse  than  useless. 

2.  A  very  large  proportion  of  the  works  will  be  constructed  to  meet 
sudden  emergencies.  Opportunities  to  plan  and  carry  out  works  a  consider- 
able time  in  advance  of  need  therefor  will  be  comparatively  infrequent. 

3.  The  fundamental  economic  principle  of  military  engineering  is  that 
time  is  of  the  essence.  Cost  and  durability  of  works  are  ordinarily  matters 
of  minor  importance.     The  quickest  makeshift  is  usually  the  best  solution. 

4.  Simplicity  must  characterize  all  designs. 

5.  Materials  which  are  available  at  or  near  the  site  of  the  work  must  be 
utilized  to  the  fullest  possible  extent. 

6.  There  will  usually,  but  not  always,  be  ample  common  labor  available, 
but  a  dearth  of  skilled  labor  of  all  classes. 

7.  As  a  rule,  no  heavy  construction  plant  and  only  the  simplest  tools  and 
materials  will  be  available. 

The  works  resulting  from  these  conditions  are  of  a  very  simple 
nature.     The  highest  expression  of  the  skill  of  the  mihtary  engi- 


34  THE  ENGINEER  IN  WAR 

neer  is  this  very  simplicity,  and  the  rapid  adaptation  of  his  de- 
signs to  the  tactical  requirements  of  the  situation  and  to  the 
resources  in  men,  tools,  materials  and  the  time  at  his  disposal. 

The  following  brief  summary  of  some  of  the  more  usual  and 
important  operations  of  the  military  field  engineer  will  serve  to 
illustrate  the  principles  hereinbefore  enunciated. 


CHAPTER  IV 
STREAM  CROSSINGS 

The  ability  to  cross  streams  is  essential  to  the  mobility  of  the 
army  and  to  facilitate  such  passage  is  one  of  the  chief  duties 
of  the  engineers.  The  history  of  war  is  replete  with  examples 
of  delays  and  failures  due  to  the  lack  of  equipment  for  the 
rapid  construction  of  bridges. 

On  the  26th  of  January,  1814,  Napoleon  writes,  "If  I  had 
had  10  pontons,  I  should  have  captured  10,000  wagons,  beaten 
Prince  Schartsenburg  in  detail,  annihilated  his  army  and  closed 
tlic  war;  but  for  want  of  proper  means  I  could  not  cross  the 
Seine." 

Writing  to  the  Adjutant  General  under  date  of  May  18,  1846, 
(lenoral  Zachary  Taylor  says:  **My  very  limited  means  for 
crossing  rivers  prevented  a  complete  prosecution  of  the  victory 
of  the  9th  (Palo  Alto).  A  ponton  train,  the  necessity  of  which 
I  exhibited  to  the  department  last  year,  would  have  enabled 
the  army  to  cross  on  the  evening  of  the  battle,  taken  this  city, 
with  all  the  artillery  and  stores  of  the  enemy,  and  a  great  number 
of  prisoners — in  short,  to  destroy  entirely  the  Mexican  Army." 

BRIDGES 

The  passage  of  streams  is  so  very  important  and  necessary 
that  the  mobile  army  can  not  afford  to  rely  entirely  upon  make- 
shifts improvised  from  materials  collected  at  the  site,  as  the  above 
quotations  will  show.  Indeed,  in  the  case  when  a  large  army 
with  its  heavy  trains  is  confronted  with  a  wide  and  deep  cross- 
ing the  construction  of  an  improvised  bridge  might  require  weeks 

35 


36 


THE  ENGINEER  IN  WAR 


STREAM  CROSSINGS 


37 


(f  time.  The  shifting  tactical  requirements  do  not  wait  on 
ach  delays  and  to  meet  such  situations  some  form  of  portable 
ridge  with  floating  supports  is  absolutely  necessary.  Ac- 
cordingly, all  modern  armies  carry  such  bridges  which  are  known 
as  ponton  equipage. 

The  equipage  in  use  in  our  army  was  devised  prior  to  the 
civil  war  and  used  with  conspicuous  success  throughout  that 
great  conflict.  It  is  a  tribute  to  the  wisdom  of  those  who  de- 
vised it  that  in  over  fifty  years  no  radical  changes  have  been 
made.  The  equipage  is  one  of  the  simplest  and  most  cunning 
of  military  expedients. 


I  ^^r^ 


FiQ.  4. — Trestle  span  of  portable  bridge  equipage. 

There  are  two  forms  of  the  equipage,  known  as  the  heavy  and 
light.  In  the  heavy  equipage  the  supports  or  piers  are  wooden 
boats  called  pontons  (Figs.  2  and  3).  They  are  31  ft.  X  5  ft.  8  in. 
X  2  ft.  7  in.,  weigh  1,600  lb.  and  have  a  displacement  of  93^  tons 
each.  For  the  shallow  portions  of  the  stream,  portable  trestles 
consisting  of  two  legs  and  a  cap,  which  is  held  in  position  by 
wedges,  are  provided  (Figs.  4  and  5).  The  roadway  is  supported 
by  stringers  or  balk  of  white  pine,  27  ft.  long  and  5  in.  square. 
The  number  of  balk  in  a  span  varies  from  5  to  11,  according  to 
the  load  to  be  carried.  In  the  first  boat  the  balk  rest  on  a 
saddle  in  the  middle,  which  forms  a  hinge  to  allow  for  changes  in 


38 


THE  ENGINEER  IN  WAR 


the  level  of  the  water  (Fig.  11).  In  the  other  boats  the  balk 
rest  on  the  gunwales.  All  fastenings  are  by  means  of  lashings. 
The  deck  consists  of  plank  IJ^  in.  X  12  in.  X  13  ft.  of  white 
pine,  called  chess.  They  are  held  in  position  by  side  rails  laid 
on  the  deck  at  its  edge  and  lashed  at  intervals  to  the  balk  be- 
low, the  lashings  passing  through  notches  in  the  plank  (Fig.  5). 
The  pontons  are  held  in  position  by  a  system  of  upstream  and 
downstream  anchors.  The  distance  from  center  to  center  of 
supports  is  20  ft. 


Fig.  5. — Portable  trestle  bridge  of  regular  equipage.  Note  abuiim-iii  .sill, 
balk  and  side-rail  lashings.  This  bridge  can  be  constructed  in  a  few  niiiiute.s. 
It  will  carry  the  heaviest  loads  which  accompany  the  army. 

The  light  train  is  similar  to  the  heavy,  except  that  the  ponton 
boats  consist  of  a  framework  covered  with  heavy  waterproof 
canvas  and  can  be  dismantled  for  transport  (Figs.  0,  7  and  8). 
They  have  a  buoyancy  of  6  tons,  the  balk  are  shorter  and  lighter, 
the  span  between  supports  is  16  ft.,  and  the  roadway  narrow(^r. 
The  two  trains  may  be  combined  in  one  bridge. 

This  material  is  all  transported  on  wagons  (Figs.  3  and  7)  and 
is  sufficiently  mobile  to  accompany  the  troops  on  the  march. 


STREAM  CROSSINGS 


39 


i 


1 


1 


40'  THE  ENGINEER  IN  WAR 

The  light  train  can  keep  pace  with  cavah-y.  The  roadway  will 
support  the  heaviest  loads  that  accompany  the  army  with  a 
factor  of  safety  of  four.,  This  bridge  can  be  laid,  crossed  and 
taken  up  in  far  less  time  than  any  other  form  of  bridge  ever 
devised  can  be  constructed.  The  weight  of  the  heavy  equipage, 
including  the  wagons  on  which  it  is  carried,  is  315  lb.  per  running 
foot  of  bridge;  of  the  light  equipage,  275  lb.  Not  including 
wagons,  the  weights  are  169  lb.  and  128  lb.  respectively.  It 
will  be  interesting  to  compare  these  weights  with  those  of  other 
forms  of  bridge  of  equal  capacity. 


Fig.  8. — Assembling  the  canvas  ponton. 

There  is  a  regular  routine  for  construction  and  so  wonderfully 
simple  is  the  equipage  that  unskilled  men  can  be  taught  to  use 
it  in  a  very  short  time.  The  bridge  may  be  constructed  by 
pushing  out  successive  pontons  from  one  or  both  banks  (Figs. 
9  and  10)  by  constructing  parts  along  shore  and  floating  them  to 
position,  or  by  constructing  the  entire  bridge  along  the  bank 
and  then  revolving  it  into  position.  The  first  method,  known  as 
"successive  pontons"  is  the  one  usually  employed.  The 
procedure,  as  laid  down  in  the  "Engineer  Field  Manual,  U.  S. 


STREAM  CROSSINGS 


Side  Rails    -        Balk 
Chess       _X 

r 


Fig.  9. — Constructing  bridge  by  successive  pontons. 


Fig.  10. — Constructing  bridge  by  successive  pontons.     Two  trestles  are 
placed,  and  the  first  ponton  with  saddle  m  center  is  in  position. 


42 


THE  ENGINEER  IN  WAR 


Fig.  11. — Completed  bridge  of  heavy  equipage.     Note  saddle  in  first  boat. 


Fia.  12. — Completed  bridge  of  light  (canvas)  equipage. 


STREAM  CROSSINGS 


43 


L.... 

^fterpendicular  to  the  bridge  axis  and  secured  by  pickets,  two  at 
ISach  end  (Fig.  5).  If  necessary,  one  or  more  trestle  spans  are 
then  placed  and  the  first  floating  support  is  brought  to  the  bank 
opposite  the  abutment.  The  free  ends  of  cables  fastened  to 
the  bank  30  paces  above  and  below  are  passed  to  men  aboard 
the  ponton.  A  set  of  balk  is  brought  up  and  the  cleats  engaged 
l^ki  the  saddle  of  the  ponton  and  lightly  held  by  lashings.     The 


Fig.  13. — Draw  span  in  ponton  bridge.     (Spanish  ponton  equipage.) 

ponton  is  pushed  off  until  the  cleats  at  inner  end  of  balk  engage 
the  abutment  sill  and  the  mooring  lines  made  fast.  The  balk 
are  then  lashed  securely  to  the  saddle  and  the  chess  (deck 
plank)  laid.  The  next  ponton  is  then  brought  alongside  and  its 
anchor  lines  (previously  placed  by  another  boat)  passed  aboard. 
The  operations  are  repeated  until  the  other  shore  is  reached. 
The  bridge  is  dismantled  in  reverse  order  (Figs.  11  and  12).  If 
the  bridge  is  to  be  in  position  for  some  time  a  movable  section 


44  THE  ENGINEER  IN  WAR 

or  draw  may  be  placed  in  the  middle  to  allow  the  passage  of 
vessels,  drift,  etc.  The  draw  consists  of  two  boats  with  a  span 
of  decking  between  (Fig.  13). 

The  construction  of  these  bridges  is  one  of  the  most  pic- 
turesque and  interesting  of  military  operations.  The  adaptability 
of  the  equipage  is  very  great  and  improvised  floating  supports, 
such  as  boats,  rafts  and  casks,  may  be  used  to  supplement  the 
regular  equipment. 

An  indication  of  the  astonishing  capacity  and  speed  of  con- 
struction of  which  the  ponton  equipage  is  capable  is  afforded 
by  the  following  historical  example : 

In  his  attempt  to  reach  the  south  side  of  the  James  River  for 
the  attack  on  Richmond  in  1864,  Grant  decided  to  throw  a 
bridge  across  at  Fort  Powhatan,  near  Charles  City.  The 
approaches  were  built  on  June  13th.  The  floating  equipage  was 
brought  up  from  Fort  Monroe  on  June  15th  and  the  bridge  was 
laid  between  4:00  p.m.  and  11:00  p.m.  of  that- day.  It  was  built 
from  both  ends.  The  bridge  was  2,200  ft.  lo^  and  101  wooden 
pontons  were  used.  The  depths  were  so  gr^t  and  the  current 
so  swift  that  several  schooners  were  moored  in  the  river  to  carry 
the  upstream  cables  of  the  bridge.  In  a  letter  to  the  Chief  of 
Engineers,  Gen.  Benham,  who  constructed  this  bridge,,  says : 

"...  I  presume  you  will  be  glad  to  hear  of  the  success  of  our  ponton 
bridge,  over  2,000  feet  long,  over  the  James  River  just  above  Fort  Pow- 
hatan, which  I  had  placed  there  on  the  evening  of  the  15th.  .  .  . 
About  11 :  00  a.m.  on  the  15th  I  received  the  order,  and  was  under  way  in 
half  an  hour,  arriving  at  the  position  selected  at  about  5: 00  p.m.  Therp 
I  found  Gen.  Meade  and  Gen.  Weitzel,  which  latter  had  prepared  the 
approaches  and  had  the  abutment  commenced.  I  was  at  once  directly 
charged  with  the  laying  of  the  bridge  by  Gen.  Meade  with  the  regulars 
to  assist  the  volunteers,  and  he  smiled  when  I  told  him  I  should  not 
sleep  till  the  bridge  was  laid. 

"I  distributed  my  men  at  once,  the  regulars  at  the  east  end,  the  volun- 
teers at  the  west  end,  and  a  company  of  volunteers  to  prepare  a  raft 
by  my  plan  of  simultaneous  bays. 


I  STREAM  CROSSINGS  45 

"At  about  10:30  p.m.  I  received  a  dispatch  from  Gen.  Meade  asking 
the  progress  of  the  bridge,  to  which  I  was  able  to  reply  at  once  that  the 
last  boat  was  in  position,  and  the  raft  of  three  boats  built  ready  to  close 
the  gap  he  had  ordered  left  for  the  present,  and  that  it  was  ready  for 
completion  in  fifteen  minutes  at  any  time  he  ordered.   .    .    . 

"  For  the  next  forty  hours  after  6  a.m.  of  the  16th,  a  continuous  stream 
of  wagons  passed  over  the  bridge  (from  4,000  to  6,000  wagons),  some 
said  fifty  miles  of  wagons — and  nearly  all  the  artillery  of  this  army,  and 
by  far  the  larger  portion  of  the  infantry  and  all  its  cavalry  present,  and 
even  to  its  herd  of  3,000  or  more  of  beef  cattle  (the  most  injurious  of  all) 
without  accident  to  man  or  beast. 

"My  officers  and  men  were  scarcely  allowed  any  sleep  during  this  time 
nor  myself  as  much  as  four  hours  in  the  eighty  hours  preceding  the  tak- 
ing up  of  the  bridge,  for  it  was  in  anxiety,  not  to  say  trembling,  that  I 
saw  the  destinies  of  the  whole  army  of  our  country  even  committed  to  this 
single,  frail,  boat  bridge,  with  steamers  and  other  boats  drifting  against 
it  and  with  much  of  its  planking  previously  worn  almost  entirely  through 
by  careless  use  upon  the  Rappahannock,  and  I  dared  not  stop  the  living 
stream  of  men  or  matter  to  sheath  or  protect  it. 

"At  length  by  7  a.m.  on  the  18th,  the  last  animals  were  over  and  I 
breathed  free  again,  and  although  the  shelling  of  our  troops  across  the 
river  just  before  sunset  within  a  mile  above  us  gave  us  little  hope  of 
withdrawing  the  bridge  in  safety,  it  was  ordered  up  and  all  rafted  into 
three  tows  before  3  a.m.  of  the  19th,  and  on  its  way  to  this  point,  which 
it  reached  about  sunrise,  the  most  successful  effort  on  a  large  scale  with 
ponton  bridging  that  has  ever  occurred  in  our  country,  if  it  does  not 
rival  those  in  any  other  land.  .    .    . 

"You  may  be  sure  I  was  very  well  content  and  satisfied  and  felt  like 
'him  that  putteth  off  his  armor,'  when  the  affair  was  over." 

This  is  an  interesting  chapter  in  the  annals  of  bridge  en- 
gineering. 

While  great  reliance  will  be  placed  upon  the  ponton  equipage, 
it  can  not  entirely  obviate  the  necessity  for  hastily  constructed 
bridges  of  other  tjrpes,  which  must  frequently  be  improvised 
from  materials  found  near  the  site.  Such  bridges  are  known  as 
''bridges  of  circumstance."  Considerable  skill  on  the  part  of 
the  engineer  officers  will  be  required  to  adapt  the  bridge  to  the 


46 


THE  ENGINEER  IN  WAR 


site  and  materials  available  to  produce  the  quickest  results. 
The  construction  of  a  bridge  is  an  interesting  task,  and  there  is 
a  strong  tendency  to  put  in  a  bridge  when  a  reconnaissance  a 
little  up-  or  downstream  would  have  revealed  a  practicable  ford, 
or  to  build  a  bridge  at  a  site  where  an  improved  ford  with  suitable 
approaches  would  have  served  the  purpose  at  a  far  less  expendi- 
ture of  time. 

The  engineer  confronted  with  a  stream  crossing  seeks  first  a 
practicable  existing  bridge  and  in  contemplation  of  a  movement 


Fid.    1  1.  — Siini)l('  pile  tre.-jtle. 

of  troops  all  important  bridges  that  may  be  used  should  be  seized 
in  advance  to  prevent  destruction  by  the  enemy  or  his  sympa- 
thizers. Even  if  the  bridge  is  insufficiently  strong  or  has  been 
damaged  it  can  often  be  repaired  or  strengthened  in  less  time 
than  a  new  bridge  could  be  built. 

The  number  of  types  of  these  improvised  bridges  is  naturally 
very  great,  but  a  few  of  them  have  been  found  especially  adapted 
to  military  uses. 


STREAM  CROSSINGS 


47 


I 

pr  The  most  common  type  is  the  simple  two-legged  trestle, 
frame  or  pile,  which  can  be  adapted  to  a  great  variety  of  condi- 
tions. The  relative  time  and  difficulty  of  constructing  the  piers 
and  spans  will  fix  the  economic  length  of  span.  For  military 
purposes  this  will  usually  be  10  to  15  ft.  and  for  such  a  span  longi- 
tudinal bracing  will  usually  be  unnecessary  (Fig.  14).  But  if 
the  water  is  very  deep  or  the  banks  high,  so  that  large  trestles 


I'lG.   lo. — Driving  })ilob  with  portable  driver.     The  float  is  of  ponton  equip- 
age, and  the  hoist  is  operated  by  a  gasoHne  engine. 

are  required,  it  will  often  be  better  to  reduce  their  number  and 
increase  the  span,  employing  more  stringers  or  some  form  of 
hght  truss.  To  reduce  the  size  of  trestles  the  approaches  may 
be  cut  down.  In  selecting  a  site  the  time  of  construction  for 
bridge  and  approaches  should  be  considered.  Ordinarily  a 
locality  where  the  stream  banks  are  low  and  firm  and  of  equal 
height  with  a  short  span  will  be  the  best  site.     If  the  depth  be 


48 


THE  ENGINEER  IN  WAR 


moderate  and  the  bottom  firm  the  framed  trestle  will  be  best. 
If  necessary  a  mud  sill  may  be  used  to  increase  the  bearing  power 
and,  if  the  depth  is  considerable  or  the  current  swift,  the  trestles 
may  be  weighted  down  by  boxing  their  sills  and  filhng  with  stone. 
While  the  two-legged  trestle  is  the  favorite  type,  three  or  four- 
legged    (sawhorse)   trestles  may  be  employed.     Cross   bracing 


Fig.  16. — Portable  pile  driver  with  swinging  leads  and  gasoline  hoist. 

of  trestles  is  always  necessary  and  for  long  spans  longitudinal 
bracing  may  be  required.  For  very  high  trestles,  two  or  three 
stories  may  be  used.  Almost  any  materials  can  be  utilized 
for  trestle  bridges,  even  bamboo  has  been  successfully  employed 
to  carry  heavy  loads.  In  considerable  depths  with  a  soft  bottom 
pile  trestles  are  often  to  be  preferred.  A  hasty  pile  driver  may 
be  improvised  with  a  heavy  block  of  wood  raised  by  tackle  and 


STREAM  CROSSINGS 


49 


guided  by  a  "spider"  and  a  few  upright  poles.  Of  course  a 
light  portable  power  driver  or  hammer  will  be  very  useful  in 
such  situations  if  available  (Figs.  15  and  16). 

For  very  soft,  yielding  bottoms,  especially  if  suitable  piles  are 
not  available,  simple  log  cribs  filled  with  stone,  if  necessary,  may 
be  employed  in  conjunction  with  trussed  spans.  Material  suit- 
table  for  cribs  is  usually  easily  obtained  and  handled. 


^-««^ 

^E 

mB 

^^H       ^B 

Fig.  17. — Truss  bridge  constructed  in  field  by  engineer  troops.     The  spans 
are  90  ft.  and  the  roadway  16  ft. 

The  purpose  of  trusses  is  to  reduce  the  number  of  supports. 
In  military  field  operations  the  use  of  trusses  will  usually  be 
hmited  to  situations  where  they  can  be  placed  with  the  aid  of 
animals  and  tackle  and  without  false-work.  If  it  be  necessary 
to  place  false-work,  this  will  usually  serve  to  carry  the  deck  and 
no  truss  will  be  needed.  If  the  bridge  is  to  be  used  for  some  time 
and  there  is  danger  from  flood  or  ice,  large  trusses  may  be  placed. 
Such  work  would  seldom  fall  to  the  lot  of  the  pioneer  engineer 


50 


THE  ENGINEER  IN  WAR 


troops.  An  excellent  example  of  a  large  military  truss  bridge 
is  that  built  over  the  Kansas  River  at  Fort  Riley,  Kans.,  by  the 
3d  Battalion  of  U.  S.  Engineers,  and  described  in  Engineering 
Record,  July  11-18,  1908  (Fig.  17).  The  usual  forms  of  truss 
will  be  the  simple  king-post  (or  triangular  truss)  and  queen- 
post,  erect  or  inverted,  with  tension  members  of  iron  rods  or 
steel  cable.  Small  Howe  or  Pratt  trusses  and  lattice  or  bow 
string  girders   of  plank   spiked   together   are   often   employed 


Fig.  18a. — Simple  trusses. 

(Figs.  18a  and  6).  The  difficulty  of  placing  trusses  without  tho 
aid  of  plant  ordinarily  limits  their  span  to  about  40  ft.  the  larger 
trusses  being  built  in  place  when  practicable.  Under  special  con- 
ditions, as  where  the  truss  may  be  floated  to  position  on  a  barge, 
greater  spans  may  be  practicable. 

In  many  situations  the  spar  lock  bridge,  which  in  double  lock 
is  practicable  up  to  45-ft.  span,  may  be  constructed  more  easily 
and  quickly  than  a  truss.  The  supports  of  this  type  consist 
of  two  tall  trestles  erected  on  or  near  the  bank  and  tilted  over 


STREAM  CROSSINGS 


51 


>7^  ^T 


ELEVATION 

FiQ.  186. — Simple  trusses. 


52 


THE  ENGINEER  IN  WAR 


until  their  heads  lock  amidstream,  forming  a  point  of  support. 
This  is  called  single  lock.  In  double  lock  the  trestles  are  tilted 
until  they  lock  with  a  frame  placed  between  them,  this  frame 
forming  one  central  span.  This  type  has  pecuhar  advantages 
from  the  mihtary  point  of  view  as,  where  applicable,  it  can  be 
very  quickly  constructed  of  the  roughest  materials  (Figs. 
19,  20  and  21). 

Clear  spans  of  more  than  50  ft.  should  usually  be  avoided  by 
seeking  a  more  favorable  site.  When  such  can  not  be  found  a 
suspension  bridge  will  usually  be  the  only  type  which  will  meet 


i>f<^y 


Fig.  19. — Spar  bridges. 

mihtary  requirements  and,  for  moderate  loads,  is  practicable  for 
long  spans.  The  essential  part  of  a  suspension  bridge  is  the 
cables,  and  if  these  are  available,  the  balance  of  the  material  is 
usually  readily  obtained.  A  great  variety  of  materials  have  been 
employed  for  cable  including  manila  rope,  chains,  bamboo,  etc. 
The  best  material  for  cables,  of  course,  is  wire  rope,  and  when 
the  necessity  for  such  bridges  is  possible  a  supply  of  rope  with 
fittings  should  be  carried  by  the  engineers.  Adjustable  sus- 
pension rods  or  hangers  may  also  be  provided  in  advance — 
cable  will  serve  this  purpose.     On  account  of  the  difficulty  of 


STREAM  CROSSINGS 


53 


handling  and  fastening  large  cables  they  should  be  Hmited 
to  ^  in.  or  1  in.,  multiple  cables  being  used  when  necessary. 
The  first  step  in  construction  is  to  erect  the  towers  and  prepare 
the  anchorages  for  the  cables.  The  towers  will  usually  be  of 
timber  and  of  the  sawhorse  trestle  type,  to  resist  overturning  both 
during  construction  and  subsequently,  as  no  roller  bearings  are 
employed    and    vertical  reactions  can  not  always  be  insured. 


1 

1 

'''■  -^ 

— 1 

m  ^ 

i»r. 

m          ^                    •  .   TT 

?Kt^S3 

1 

if 

m 

^m\ 

/ 

♦ 
i 

j^^®5^      N                                                W 

^-^ 

jiSiJ^i'^'' 

! 

> 

i__j — 

Fia.  20. — Double  lock  spar  bridge. 

Standing  trees  may  occasionally  be  utiUzed  for  towers.  The 
anchorages  consist  of  large  logs  in  trenches  (deadmen),  standing 
trees  or  stumps,  large  boulders  or  ledges  of  rock,  where  available. 
Occasionally  concrete  is  employed.  The  cable  may  be  dragged 
across  the  towers  or  laid  out,  measured  and  anchored  (tem- 
porarily at  one  end  to  allow  adjustment)  on  the  ground  and  then 
lifted  to  the  towers.  The  sag  of  the  cables  will  usually  be  con- 
siderable.    This  decreases  the  strain  on  the  cables  but  makes 


54 


THE  ENGINEER  IN  WAR 


the  bridge  very  liable  to  undulation  under  live  loads.  Slings  or 
suspension  rods  may  be  cable,  wire  rope,  manila  rope,  round  iron, 
or  even  wood.  From  each  pair  of  slings  hangs  a  transom  or  road- 
way bearer,  on  which  the  stringers  and  deck  are  placed  (Figs. 
22  and  23). 


Fig.  21. — Double  lock  spar  bridge  with  suspended  roadway. 

are  lashings. 


All  fastenings 


Oscillations  and  undulations  may  be  controlled  by  lateral 
trussing  of  the  roadway,  by  a  trussed  guard  rail,  by  drawing  the 
cables  together  at  the  center  of  the  span,  and  by  guys. 

In  many  situations  a  combination  of  types  meets  requirements 
better  than  any  single  type.     Such  combinations  might  include 


I 


STREAM  CROSSINGS 


55 


KiG.  22. — Field   suspension    bridge,    roadway   of   ponton   material. 
waKon  is  the  stanthinl  engineer  tool  wagon. 


The 


^M 

- 

"^  ^ 

m 

Fig.  23. — A  Spanish  suspension  bridge  in  the  Philippine  Islands  rebuilt  for 
military  use.     Only  the  towers  of  the  old  bridge  remained. 


56  THE  ENGINEER  IN  WAR 

frame  and  pile  trestles,  trestles  and  truss  spans,  a  combination 
of  trestles  and  floating  supports,  the  latter  being  a  very  usual 
expedient. 

The  deck  or  roadway  should  be  no  wider  than  necessary,  both 
because  of  the  weight  and  extra  time  required  for  construction: 
Ordinarily  two  lines  of  vehicles  will  not  be  passing  in  opposite 
directions  at  the  time  same.  Twelve  feet  is  usually  quite 
sufficient  for  a  wagon  bridge,  allowing  for  the  passage  of  foot  or 
horsemen  alongside  the  wagons.  For  a  foot  bridge  alone  a  less 
width  is  required.  Side  rails  are  always  provided  but  hand 
rails  are  seldom  used  except  on  through  truss  and  suspension 
bridges. 

The  stringers  may  be  of  round  or  sawed  lumber.  Planking 
IJ^  in.  or  more  in  thickness  makes  the  best  deck.  Where  this  is 
not  available  the  deck  may  be  of  poles  held  in  place  by  side  rails 
and  covered  with  brush,  leaves  and  earth  or  gravel.  This  makes 
a  satisfactory  deck  but,  except  in  short  span  trestle  bridges,  is 
objectionable  because  of  its  weight  (Figs.  19  and  20). 

The  fastenings  are  of  the  simplest  nature,  lashings,  spikes  and 
bolts  being  used.     Elaborate  framing  is  avoided  as  far  as  possible. 

FORDS 

Before  entering  upon  the  construction  of  a  bridge  search 
should  be  made  for  a  practicable  ford,  if  the  nature  of  the  stream 
gives  any  promise  that  such  may  be  found.  Fords  which  have 
been  used  by  the  local  inhabitants  should  be  first  examined. 
In  determining  the  practicability  of  a  ford  the  considerations  are: 
(a)  nature  of  approaches;  (6)  nature  of  bottom;  (c)  depth  of  water; 
and  (d)  velocity  of  current.  For  the  passage  of  mounted  troops 
and  wagons  the  approaches  may  be  improved  by  cutting  down 
the  banks  to  ease  the  grades,  and  by  surfacing  the  roadway  with 
plank,  brush,  gravel,  etc.  A  sandy  bottom  is  the  most  favorable 
and  usually  requires  no  improvement.  If  the  bottom  be  rocky 
or  yielding  it  may  be  made  practicable  by  a  deposit  of  sand  or 


STREAM  CROSSINGS 


57 


•avel,  by  fascines  or  bundles  of  brush,  or  by  a  woven  mattress 
ink  in  position.  The  limiting  practicable  depths  of  fords  where 
the  current  is  sluggish  are:  for  infantry,  4  ft.;  for  cavalry,  5  ft.; 
for  artillery  or  wagons,  2}4  ft.  If  the  current  is  swift  the  depths 
For  infantry  and  cavalry  are  3  ft.  and  4  ft.  respectively.  A  hfe 
ine  may  be  stretched  across  the  stream  to  facihtate  the  passage 
of  infantry.  Ice  2  in.  thick  will  support  infantry  in  single 
file;  4  in.  thick,  cavalry  at  intervals;  5  to  6  in.  heavy  field  pieces. 


Lundiiig  wharf  and  pile  driver  of  pun  tun  material. 


FERRIES 

When  fording  is  impracticable  and  there  is  not  time  nor 
material  for  a  bridge,  resort  may  be  had  to  a  ferry.  These  will 
be  used  especially  in  cases  of  wide  crossings,  where  time  is  of 
special  importance  and  when  the  number  of  troops  to  cross  is 
small.  The  ponton  equipment  heretofore  described  is  specially 
designed  with  a  view  to  its  use  for  ferrying  purposes.  The 
pontons  of  the  heavy  train  will  carry  from  20  to  40  foot  troops,  in 
addition  to  the  crew.  A  raft  or  catamaran  made  of  two  pontons 
with  a  span  of  flooring  between  will  carry  cavalry,  artillery  and 
wagons.  In  the  absence  of  the  ponton  equipment  rafts  may  be 
constructed  of  logs,  casks,  etc. 


58 


THE  ENGINEER  IN  WAR 


If  the  current  be  swift  a  rope  may  be  stretched  from  bank 
to  bank  and  the  float  drawn  across  by  hand.  Or  the  current 
may  be  made  to  furnish  motive  power  by  attaching  a  block  to 
the  rope  and  securing  the  float  to  the  block  in  such  a  manner  as 


Fig.  25. — Trail  ferry  and  landing  of  ponton  equipage. 


to  hold  it  at  an  angle  to  the  current.  In  the  flying  bridge  the 
float  is  attached  to  and  swings  in  a  circle  on  a  line  anchored  well 
upstream.  The  current  may  be  made  to  furnish  motive  power, 
as  in  the  former  case,  or  the  ferry  may  be  drawn  across  by  an 
auxiliary  line  secured  to  the  bank  (Figs.  24,  25  and  26). 


STREAM  CROSSINGS 


59 


Fig.  26. — Flying  ferry. 


60  THE  ENGINEER  IN  WAR 

EXAMINATION  AND  REPAIR  OF  SIMPLE  HIGHWAY  BRIDGES 

An  important  problem  with  which  the  military  engineer  will 
often  be  confronted  is  that  of  determining  the  supporting  power 
or  safe  load  of  an  existing  bridge,  and  the  methods  that  may- 
be adopted  to  strengthen  the  structure.  Good  civil  practice 
has  resulted  in  the  adoption  of  type  plans  for  the  various  forms 
of  bridges,  the  safe  loads  of  each  being  carefully  specified. 
Commercial  traffic  is  usually  heavier  than  that  which  accompanies 
the  mobile  army  and  accordingly  a  well-designed  bridge  may 
generally  be  pronounced  safe  for  military  use,  provided  an 
examination  shows  that  it  is  in  good  condition.  Also  the  factor 
of  safety  may,  in  such  a  case,  be  reduced  from  5  or  6  to  2} '2  or 
3,  if  this  be  necessary.  But  in  our  country  we  encounter  many 
bridges  which  are  not  designed  in  accordance  with  good  practice. 
Many  of  them  arc  not  designed  at  all,  and  in  many  steel  bridges 
economy  of  material  is  carried  to  an  extreme,  the  designers  trust- 
ing in  Providence  that  the  bridge  will  never  be  tested  to  the 
specified  loading. 

The  quickest  method  of  determining  the  carrying  capacity  of 
a  bridge  is  by  comparing  it  mentally  with  other  similar  bridges 
whose  capacity  is  known.  This  will  require  considerable  expe- 
rience and  great  power  of  observation  on  the  part  of  the  engi- 
neer. To  calculate  accurately  the  carrying  capacity  of  a  bridge 
may  be  a  tedious  operation,  but  approximate  methods  or  "rules 
of  thumb,"  which  any  competent  engineer  can  devise  for  him- 
self, will  usually  give  results  sufficiently  close  for  practical 
purposes. 

An  examination  of  the  bridge  by  an  experienced  engineer  will 
usually  serve  to  indicate  the  weakest  or  critical  parts  of  the 
structure,  to  which  special  attention  should  be  given. 

A  useful  formula  for  bridge  stringers  of  wood,  such  as  are 
often  encountered,  is  the  following: 

Safe  center  load  in  pounds  times  span  in  feet  equals  A 
times  BD^.  In  this  formula  A  is  a  factor  depending  on  the  kind 
of  wood,  and  B  and  D  are  the  breadth  and  depth  of  the  stringers 


STREAM  CROSSINGS 


61 


in  inches.  For  a  factor  of  safety  of  3,  A  may  be  taken  as  at 
least  100  even  for  rather  poor  timber.  Hence,  if  a  wooden 
fstringer  is  to  be  safe,  BD^  should  equal  the  span  in  feet  times  the 

W 
jenter  load  in  hundred  weights,  BD^  X  L  X  y^^.     The  weight 

)f  the  beam  itself  may  be  disregarded.  The  safe  uniform 
load  may  be  taken  as  double  the  safe  concentrated  center  load. 
[If  the  deck  is  sufficiently  heavy  the  equivalent  center  load  on 
any  one  stringer  should  not  exceed  about  30  per  cent,  of  the 
weight  of  the  army  wagon  or  artillery  carriage.  Under  this 
assumption  the  rule  gives  the  following: 

For  loaded  wagons  or  light  artillery,  BD^  =  or  >  20  X  span. 

For  heavy  field  artillery,  4.7  in.  guns,  BD^  =  or  >  30  X  span. 
If  the  span  is  less  than  15  ft.,  the  span  multipliers  may  be  re- 
duced one-third. 

A  convenient  rule  of  thumb  for  the  deck,  if  of  wood,  is  that 
the  thickness  of  the  deck  in  inches  should  be  as  great  as  the  in- 
tervals between  stringers  in  feet.  Thus,  if  the  stringers  are 
3  ft.  apart  the  decking  should  be  3-in.  planking. 

If  the  stringers  are  standard  steel  I  beams  their  safe  loads 
vary  approximately  with  the  square  of  the  depth.  Also  the 
fiber  strength  is  about  10  times  that  of  wood.  Hence  the  rules 
become  for  long  spans: 

For  loaded  wagons,  D^  =  or  >  2  X  span. 

For  heavy  field  artillery,  2)^  =  or  >  3  X  span. 

These  rules  are  but  rough  approximations,  but  they  serve  for 
practical  purposes,  and  afford  a  test  of  the  strength  of  the  floor 
system.  If  this  be  safe  the  remainder  of  the  bridge  timbers  are 
probably  right,  since  good  design  demands  this  condition,  and 
the  floor  system  is  most  subject  to  wear  and  decay. 

However,  similar  approximations  may  be  applied  to  trestle 
caps  of  two-legged  trestles  or  the  roadway  bearers  of  small  truss 
bridges.  Assuming  the  weight  of  a  bay  with  its  load  at  20,000 
lb.,  we  have,  BD'^  =  or  >  100  X  length  of  caps;  or  for  steel  I 


62  THE  ENGINEER  IN  WAR 

beams,  D^  =  or  >  10  X  length  of  beam.  For  spans  of  less 
than  15  ft.  the  multipliers  may  be  reduced  by  half. 

The  strength  of  simple  Howe  or  Pratt  trusses  may  be  quickly 
determined  by  the  well-known  method  of  ''shear  and  chord 
increments." 

These  rules  are  applicable  to  structures  which  closely  follow 
standard  design  for  the  types  considered  and  to  the  usual  loads 
with  the  army.  Any  bridge  which  exhibits  a  radical  departure 
from  the  -usual  designs  should,  in  the  first  place,  be  looked  upon 
with  suspicion  and,  in  the  second  place,  should  be  examined  with 
more  than  ordinary  care.  If  unusual  loads  are  to  be  brought 
upon  the  structure  a  more  thorough  examination  is,  of  course, 
demanded. 

If  the  deck  planking  is  thin,  worn  or  decayed,  longitudinal 
planks  may  be  laid  under  the  wheels.  A  weak  stringer  may  be 
braced  by  placing  a  post  under  its  center,  or  a  trestle  or  crib 
may  be  inserted  at  the  center  of  the  span,  which  supports  all 
the  stringers.  Sometimes  it  will  be  easier  to  take  up  the  flooring 
and  insert  additional  stringers.  If  trestle  legs  are  over  10  or 
12  ft.  in  length  they  should  be  cross  braced,  and  if  the  spans  are 
over  15  ft.,  the  trestles  should  be  braced  longitudinally.  Wooden 
trusses  may  be  strengthened  by  spiking  or  bolting  additional 
timbers  to  the  chords  and  inserting  web  members  of  timber. 
A  weak  steel  truss  may  be  supported  by  one  or  more  trestles  or 
cribs  inserted  beneath. 

These  are  but  a  few  of  the  expedients  that  will  suggest  them- 
selves to  the  resourceful  engineer.  It  will  usually  be  easier 
to  reinforce  an  old  bridge  than  to  build  a  new  one. 

A  bridge  which  has  been  examined  or  strengthened  should  be 
placarded  to  indicate  its  safe  load. 


CHAPTER  V 
MILITARY  ROADS 

We  have  seen  that  mobility,  the  power  to  maneuver  in  stra- 
tegical and  tactical  combinations,  is  essential  to  success  in 
military  operations.  Roads  accordingly  play  an  important 
lolc  in  the  conduct  of  war.  In  modern  warfare,  with  the  vast 
number  of  combatants  engaged  and  the  great  extent  of  territory 
covered,  roads  will  be  of  more  importance  than  in  the  past. 
While  miUtary  operations  of  any  magnitude  will  be  dependent 

kupon  the  railroads  yet  the  motor  truck  has  become  a  most 
important  aid  to  the  railroad  in  the  transportation  of  troops, 
jfcrtillery  and  material  of  all  kinds.  To  realize  the  advantages 
Ihat  may  be  derived  from  its  use  an  extensive  system  of  good 
roads  is  essential.  Good  roads  saved  Paris  from  falling  into  the 
hands  of  the  Germans  during  the  present  war.  It  was  the 
steady  stream  of  soldiers  poured  into  the  firing  line  by  automobiles 
on  the  magnificent  chaussies  of  France  that  turned  the  tide  of 
invasion  at  the  Marne. 

In  road  work,  probably  more  readily  than  in  any  other  branch 
of  military  field  engineering,  the  engineer  with  civil  training 
can  adapt  his  knowledge  and  experience  to  war  conditions. 
Military  road  building  is  similar  in  many  respects  to  civil  prac- 
tice. The  civil  engineer  who  has  a  thorough  knowledge  of  the 
methods  that  produce  good  roads  and  the  broad  common  sense 
which  will  enable  him  to  apply  them  to  military  needs  will  be 
successful  in  time  of  war.  It  is  only  necessary  that  he  should 
thoroughly  appreciate  the  economics  of  warfare  which  we  have 
heretofore  discussed. 

Motor  transport  demands  good  roads  and  even  for  animal 
transport  they  are  to  be  desired.     The  construction  of  a  modern 

63 


64  THE  ENGINEER  IN  WAR 

paved  highway  takes  time  and  therefore  military  operations  will 
be  greatly  hampered  if  they  are  conducted  in  a  country  which 
has  not  been  provided  in  time  of  peace  with  a  complete  system 
of  good  roads.  In  many  parts  of  Europe  such  systems  exist 
and  the  principal  highways  have  been  built  with  a  view  to  their 
usefulness  in  war  as  well  as  in  peace.  The  United  States  is 
poorly  equipped  both  as  to  the  quantity  and  the  quaUty  of  its 
roads.  In  any  mihtary  operations  conducted  in  our  terri- 
tory, extensive  road  construction  must  be  carried  on  by  both 
combatants. 

Military  road  work  will  consist  very  largely  of  the  improve- 
ment, repair  and  maintenance  of  existing  roads,  but  in  many  of 
our  possible  theaters  of  war,  including  the  United  States  and 
other  parts  of  the  American  continent,  extensive  new  con- 
struction work  will  also  be  necessary. 

In  the  location  and  construction  of  a  military  road  the  peculiar 
economics  of  warfare,  which  have  been  heretofore  mentioned, 
should  be  kept  constantly  in  mind.  In  the  construction  of  a 
civil  road  or  railroad  the  amount  of  money  which  may  be  prof- 
itably expended  in  reducing  grades,  securing  good  alignment  and 
in  paving  (in  the  case  of  a  road)  is  determined  from  the  estimate 
of  the  nature  and  amount  of  the  probable  traffic.  In  military 
construction  the  element  of  cost  is  of  secondary  importance, 
but  the  question  of  time  is  paramount.  The  road  must  be  opened 
for  traffic  in  the  least  possible  time.  Nevertheless  the  nature 
and  amount  of  the  traffic  and  the  period  during  which  the  road 
will  probably  be  required  are  not,  of  course,  entirely  disregarded. 
The  road  will  usually  be  constructed  to  meet  the  exigency  of  the 
moment  and  may  later  be  altered  and  improved  to  meet  the 
development  of  the  situation. 

Common  labor  will  ordinarily  be  plentiful,  but  often  no  plant 
at  all  will  be  at  hand.  Wlieelbarrows  can  usually,  although  not 
always,  be  suppUed,  and  for  extensive  work  plows  and  drag  or 
wheel  scrapers  should  be  obtained.  Explosives  will  be  available 
and  may  be  Uberally  employed.     The  use  of  more  elaborate 


MILITARY  ROADS 


65 


plant,  such  as  graders,  steam  shovels,  etc.,  will  seldom  be 
practicable  or  advisable  under 
war-time  conditions.  The 
stretches  of  road  to  be  con- 
structed will  usually  be  relatively 
short  and  built  to  connect  exist- 
ing roads.  Motor  trucks  will  be 
utilized  on  the  good  existing 
loads  where  they  can  move  at 
the  relatively  high  speed  which 
is  necessary  if  their  economical 
advantages  are  to  be  realized. 
lUit  on  purely  military  roads 
l)uilt  under  service  conditions 
iimch  of  the  traffic  especially  in 
our  own  operations,  will  be  by 
wagons  drawn  by  horsos  or 
mules.  Four  and  six  line  teams 
may  be  and  are  employed  in 
miUtary  operations  when  civil 
economics  would  demand  two 
line  teams  (Fig.  27).  Also, 
military  traflfic  moves  in  trains 
and  teams  may  be  doubled  up 
and  loads  shifted  when  neces- 
sary. Extra  teams  and  relay 
stations  may  be  provided.  Such 
traffic  moves  but  slowly  on  the 
best  roads,  and  hence  the 
greatest  improvements  in  the 
road  will  effect  only  slight 
changes  in  the  speed  of  trans- 
port (though  they  may  reduce 
its  cost),  unless  motor  trucks  be 
substituted  for  wagons.    A  rough 


either 


66 


THE  ENGINEER  IN  WAR 


surface,  if  firm,  is  of  little  disadvantage  to  slow-moving  trafl&c 
and  the  same  is  true  of  poor  alignment,  though,  of  course,  very- 
sharp  curves  should  be  compensated  by  widening  the  road. 

Brick  roads  are,  of  course,  out  of  the  question,  except  possibly 
along  the  main  motor  routes  on  the  lines  of  communication. 
For  wagon  traffic  their  advantages  are  not  sufficient  to  justify 
their  cost  and,  more  particularly,  the  time  required  for  their 
construction.  Even  common  water-bound  macadam  can  seldom 
be  advantageously  employed.  The  military  road  will  usually 
be  a  common  earth  road.  If  the  soil  is  very  saijdy  it  may  be 
mixed  with  clay  for  a  wearing  surface,  and  conversely.     Gravel 


Fig.  28. — Road  improved  for  military  use  by  paving  of  logs  and  brush. 
Constructed  by  the  Germans  in  Russia. 


may  occasionally  be  used  to  good  advantage  if  it  can  be  obtained 
along  the  hne  of  the  road.  Pit  gravel  usually  compacts  very 
satisfactorily  under  traffic  if  shaped  up  occasionally.  Stream 
gravel  usually  requires  the  addition  of  a  binder.  If  the  gravel 
contains  many  large  pebbles  or  stones  it  should  be  screened. 
If  stone  is  available  a  rock  fill  covered  with  a  layer  of  earth  may 
be  emploj^ed  at  soft  spots  where  the  drainage  is  bad.  In  swampy 
or  poorly  drained  ground  a  plank  or  "corduroy"  road  will  usually 
be  the  simplest  and  best  expedient.  The  logs  or  poles  are  seldom 
covered,  and  the  surface,  while  rough,  is  firm  and  suitable  for 


MILITARY  ROADS  67 

slow-moving  traffic.  A  great  variety  of  materials  may  be  used 
to  temporarily  increase  the  supporting  power  of  a  roadbed, 
including  branches  of  trees,  bunches  of  brush,  grass,  turf, 
leaves,  etc. 

It  is  to  be  remarked  that  the  advantages  of  very  low  gradients 
can  not  be  fully  realized  unless  a  good  surface  is  also  provided 
and,  conversely,  the  advantages  of  a  good  surface  can  not  be  fully 
realized  unless  the  grades  are  held  down.  Accordingly  it  is  of 
little  use  to  strive  for  very  low  grades  on  a  road  which  is  not  to 
be  paved,  or  to  incur  great  expense  of  time  and  money  in  provid- 
ing a  macadam  paving  on  bad  grades.  A  good  macadam  road 
must  have  low  grades.  Also,  for  slow-moving  military  traffic 
neither  low  grades  nor  good  surfaces  are  as  advantageous  as  for 
motor  transport. 

Military  traffic  moves  in  trains  and  its  use  of  the  road  may  be 
regulated.  Loaded  wagons  generally  move  in  one  direction  only 
and  empties  in  the  opposite  direction.  Under  these  conditions 
a  10-ft.  or  even  an  8-ft.  width  of  road  may  be  made  to  meet 
requirements,  passing  points  being  placed  at  the  necessary  inter- 
vals and  where  the  extra  width  may  be  cheaply  provided.  Such  a 
narrow  road  would,  of  course,  be  very  unsatisfactory  for  un- 
regulated civil  traffic  with  loaded  wagons  passing  at  random  in 
both  directions  and  meeting  at  all  points.  A  width  of  16  ft. 
which  permits  the  easy  passage  of  two  lines  of  wagons  in  opposite 
directions,  is  desirable  if  it  can  be  obtained  without  excessive 
excavation.  It  will  seldom  be  advisable  to  provide  more  than  an 
8-ft.  width  of  metal  if  the  road  is  to  be  paved. 

In  the  location  of  a  military  road  the  foregoing  facts  must  be 
borne  in  mind.  In  order  to  reduce  the  excavation  to  a  minimum 
the  road  should  lie  close  to  the  natural  surface  of  the  ground, 
even  if  this  results  in  occasional  steep  and  adverse  grades,  poor 
alignment  and  consequently  increased  length.  Heavy  cuts  and 
fills  with  the  great  yardage  and  the  relatively  long  hauls  which 
they  involve  should  be  avoided.  A  gradient  generally  not 
exceeding  4  to   5  per  cent,   with  occasional  short  maximum 


68  THE  ENGINEER  IN  WAR 

stretches  of  6  to  7  per  cent,  may  be  regarded  as  quite  satisfactory 
for  military  wagon  transport  if  better  grades  can  not  be  secured 
without  excessive  labor.  A  road  having  a  grade  generally  not 
exceeding  8  per  cent,  with  occasional  maximums  of  10  or  11 
per  cent,  or  even  more,  will  be  practicable,  but  will  require  relay- 
ing if  the  distance  be  considerable.  It  may  be  adopted  if  the 
nature  of  the  terrain  does  not  allow  better  natural  grades. 
Adverse  grade  should,  of  course,  be  avoided,  even  if  this  requires 
more  distance.  In  the  original  location  an  effort  should  be 
made  to  keep  the  grades  generally  as  moderate  as  the  nature  of 
the  terrain  will  permit  without  excessive  excavation,  and  to 
concentrate  the  steeper  grades  in  a  few  localities.  The  road  is 
thus  opened  up  and  the  had  grades  may  later  be  reduced  if  neces- 
sary by  cuts  and  embankments.  By  thus  concentrating  the  un- 
favorable grades  in  a  few  localities  subsequent  improvements 
may  be  effected  with  the  least  possible  relocation  and  interrup- 
tion to  traffic.  Thus  if  there  is  a  possibility  that  the  road  may  be 
used  for  transport  for  a  considerable  period  it  will  usually  be 
better  to  adopt  a  general  grade  of  about  4  per  cent,  with  oc- 
casional sharp  maximums  8  to  10  or  even  12  per  cent,  rather 
than  a  general  grade  of  7  to  8  per  cent,  with  nothing  exceeding 
this.  In  the  former  case  a  few  relocations  in  the  maximum 
sections,  involving  perhaps  some  heavy  excavation,  will  even- 
tually produce  a  good  4  per  cent,  road,  whereas  if  the  steeper 
general  grade  were  adopted,  complete  relocation  and  reconstruc- 
tion would  be  necessary  to  produce  the  same  result.  In  the  first 
instance  the  heavy  work  is  avoided  by  a  steep  chmb  or  a  detour 
which  is  later  ehminated  and  abandoned.  Thus  the  locator 
should  consider  what  may  eventually  be  required  and  so  plan  his 
original  location  as  to  enable  the  ultimate  requirements  to  \}v 
met  with  the  least  possible  reconstruction,  even  at  the  cost  of 
temporary  disadvantage  in  the  way  of  occasional  very  steep 
grades.  If  the  future  requirements  are  uncertain  it  may  be  ad- 
visable to  adopt  a  somewhat  higher  general  grade,  suited  to  the 
nature  of  the  terrain  and  to  avoid  steep  maximums  greatly  in 


I 


MILITARY  ROADS  69 

excess  of  the  general  grade.  It  will  be  apparent  that  the  problems 
of  the  military  locating  engineer  are  not  greatly  different  from 
those  of  his  civilian  confrere.  He  must  consider  the  demands 
of  the  immediate  situation  and  meet  them  promptly,  but  so  far 
as  practicable  he  should  also  give  consideration  to  the  ultimate 
requirements.  In  locating  a  road  for  military  purposes  the  engi- 
neer enjoys  one  great  advantage  in  that  he  is  not  hampered  to  so 
great  an  extent  as  the  civiHan  by  questions  of  right-of-way, 
property  values,  etc.  And,  as  in  all  military  construction,  first 
cost  gives  way  to  speed,  which  often  simplifies  the  problem. 

The  general  location  of  the  road  is  selected  from  a  map,  if 
one  suitable  for  that  purpose  is  available.  The  next  step  is  a 
hasty  reconnaissance  or  preliminary  survey  to  fix  the  general 
location  on  the  ground,  determine  the  grades  which  may  be  ob- 
tained and  the  special  difficulties  to  be  encountered,  the  materials 
available  along  the  route,  etc.  For  this  examination  very  simple 
instruments  will  serve,  an  aneroid  barometer  for  elevations,  a 
luiiul  clinometer  to  measure  gradients,  distances  measured  by 
pacing.  A  rough  sketch  of  the  route  should  be  prepared  and  it 
'should  be  marked  out  by  placing  flags  (pieces  of  red  cloth  on 
sticks),  blazing  trees,  etc.  The  detailed  location  may  be  satis- 
factorily executed  with  the  same  instruments  in  the  hands  of 
skillful  and  experienced  men.  A  fight  transit  with  a  vertical 
limb  and  a  tape  or  stadia  rod  are  better  and  will  usually  meet  the 
roquirements. 

The  removal  of  trees,  especially  their  stumps,  is  a  slow  process 
and  it  is  therefore  well  to  avoid  timbered  areas  if  practicable. 
Also,  the  absence  of  sunUght  and  poor  ventilation  increase 
the  difficulty  of  maintaining  an  earth  road  in  a  wood  in  passable 
condition.  If  it  be  necessary  to  pass  through  a  wood  the  road 
may  be  curved  or  zigzagged  to  avoid  the  very  large  trees.  The 
best  way  to  remove  a  large  tree  is  to  dig  around  it,  cut  the  larger 
roots  and  then  pull  over  the  tree  with  blocks  and  tackle.  This 
removes  tree  and  stump.  If  stumps  are  encountered  they  can  be 
removed  only  by  explosives  which  may  be  used  fiberally  to  save 


70  THE  ENGINEER  IN  WAR 

time.  For  military  purposes  a  wooden  trestle  or  viaduct,  which 
may  be  constructed  in  a  few  hours  or  a  few  days,  is  often  pref- 
erable to  a  long  high  embankment  which  may  require  weeks  to 
construct  with  inadequate  plant,  and  will  generally  also  have  to 
be  paved  in  some  manner  to  render  it  passable.  Skill  in  location 
will  reduce  the  number  of  culverts  required,  often  it  is  true,  at 
the  expense  of  alignment.  The  road  should  follow  the  high 
ground  or  ridges,  and  the  side  ditches  may  be  led  off  into  adjacent 
ravines.  Also,  sun  and  air  are  very  important  aids  in  the 
maintenance  of  an  earth  road.  Culverts  when  employed 
should  be  of  the  simplest  type,  plank  and  corrugated  iron  pipe 
being  the  most  suitable  materials  and  sufficiently  durable  for 
military  purposes. 

The  bearing  power  of  a  road  surface  depends  upon  the  paving 
and  upon  the  drainage  of  the  roadbed.  Military  roads  will 
seldom  be  paved  and  according!}'  particular  attention  should 
be  'given  to  drainage.  Sub-drainage  will  usually  be  imprac- 
ticable but  ample  side  ditches  should  always  be  provided,  except 
in  very  dry  climates.  The  material  from  the  ditches  is  used  to 
raise  and  crown  the  roadbed.  The  best  form  of  ditch  is  one  wide 
and  shallow  rather  than  narrow  and  deep,  since  it  is  more  easily 
constructed  and  kept  open.  Such  a  ditch  may  be  constructed 
with  a  drag  scraper,  with  a  plow  to  loosen  the  earth.  If  the  road 
is  constructed  on  a  steep  sidehill,  surface  or  intercepting  ditches 
may  be  provided  to  keep  the  water  from  the  hillside  off  the  road. 
Retaining  walls  should  be  avoided  if  possible,  as  they  require 
much  time  to  construct.  Zigzags  or  switch-backs  may  be 
employed  to  save  labor  on  sidehill  work.  Retaining  walls  if 
used  are  built  of  log  cribs,  dry  rubble,  etc.  Concrete  will  seldom 
be  employed. 

One  of  the  economic  advantages  of  a  well-paved  road  from 
the  civil  engineer's  point  of  view  is  the  decreased  cost  of  main- 
tenance during  a  period  of  years.  We  are  realizing  more  and 
more  that  increased  first  cost  and  longer  time  required  for  con- 
struction are  usually  economical  for  permanent  roads  in  view 


I 


MILITARY  ROADS  71 

of  the  lower  maintenance  charges  and  the  greater  satisfaction 
from  the  use  of  the  road,  the  beneficial  effects  on  the  growth,  the 
business  and  social  life  of  the  communities  affected,  etc.  But 
we  should  also  reahze  that  from  a  mihtary  point  of  view  these 
considerations  have  little  weight.  The  army  does  not  expect 
and  does  not  demand  that  good  roads  shall  be  built  under  war 
conditions  in  the  theaters  of  actual  conflict,  and  moreover  it 
can  not  brook  the  delay  that  their  construction  would  require. 
Prompt  results  are  demanded,  cost  is  disregarded  and  make- 
shifts cheerfully  accepted.  As  military  roads  are  often  used 
For  a  very  short  time  only  and  never  beyond  the  end  of  the  war, 
'Hie  question  of  maintenance  over  a  period  of  years  does  not 
arise.  It  will  be  economical  to  build  an  inferior  road  in  the 
first  place  and  to  keep  it  passable  by  relatively  expensive  main- 
jnance  measures  during  a  relatively  short  period.  Earth  roads 
be  passable  must  be  kept  drained  and  free  from  ruts  and  for 
mihtary  roads  ample  labor  for  maintenance  will  generally  be 
available.  The  roads  should  be  kept  shaped  up,  ruts  filled, 
ditches  kept  open.  The  most  efficient  method  of  maintaining 
earth  roads  is  by  dragging,  supplemented  by  hand  labor. 


CHAPTER  VI 
FIELD    FORTIFICATION    AND    SIEGE    OPERATIONS 

Field  fortification  is  the  most  important  and  the  most  dis- 
tinctively miUtary  of  the  many  operations  of  the  field  engineer 
and  constitutes  an  art  and  a  science  in  itself. 

The  art  of  fortification  includes  two  branches,  known  as 
strategical  or  dehberate,  and  tactical  or  hasty  fortification. 

Strategical  fortifications  include  defensive  works  executed 
largely  in  time  of  peace  for  the  protection  of  important  harbors, 
cities,  arsenals,  etc.  Tactical  fortifications  are  those  executed 
to  meet  the  immediate  tactical  needs  of  the  mobile  army  in  the 
field,  and  are  hence  known  also  as  field  fortifications.  The  line 
of  demarcation  between  the  two  classes  is  not  clearly  defined. 
Strategy  and  tactics  are  intimately  connected  and  so  the  works 
constructed  to  meet  their  needs  vary  from  the  elaborate  coast 
defense  works  to  the  simple  trenches  of  a  rear  guard  fighting  a 
delaying  action. 

The  purposes  of  military  operations  are  to  destroy  the  organized 
resistance  of  the  enemy  or  to  seize  and  hold  territory  which  is 
important  to  him.  For  the  accomplishment  of  either  purpose 
aggressive  action  is  required.  This  aggressive  action  consists 
in  the  concentration  of  overwhelming  force  at  certain  critical 
points  while  the  enemy  is  held  in  check  at  other  points,  and 
it  contemplates  the  probability  of  similar  operations  on  the  part 
of  the  enemy.  MiUtary  operations  are  accordingly  a  combina- 
tion of  offensive  and  defensive  action,  and  success  will  lie  with 
the  combatant  who  can  seize  and  retain  the  initiative. 

Aggressive  action,  the  assumption  of  the  initiative,  impUes 
the  power  of  maneuver  in  strategical  and  tactical*  combinations. 

72 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS         73 

Jtrategy  maneuvers  the  troops  into  the  most  advantageous  posi- 
ion  for  battle,  but  strategical  advantages  can  in  general  be 
reaUzed  only  by  wiiming  the  battle,  which  is  their  logical  cul- 
mination.    For  success  in  battle  the  power  of  tactical  maneuver 
is  essential. 

The  immediate  purpose  of  field  fortifications  is  to  increase  the 
power  of  resistance  of  the  troops  occupying  them  by  decreasing 
their  exposure  to  the  fire  of  the  enemy  and  increasing  the  accuracy 
and  volume  of  their  own  fire.  They  thus  serve  to  hold  the  enemy 
in  check  and  limit  his  power  of  maneuver.  Furthermore,  they 
accompUsh  this  result  with  the  least  number  of  men,  thereby 
lendering  the  greatest  possible  number  available  for  aggressive 
concentration  of  superior  forces  at  the  critical  points. 

Even  in  a  successful  attack  the  assailant  can  not  advance  con- 
tinuously.  Halts  will  be  necessary  to  permit  of  the  bringing 
up  of  supplies  and  reinforcements,  to  refresh  the  troops,  to  hold 
the  enemy  in  check,  to  select  new  points  of  attack,  to  readjust 
the  artillery  positions,  etc.  The  assailant  at  all  such  halts  must 
cling  with  the  spade  to  that  which  he  has  won  with  the  rifle  and 
bayonet.  Troops  can  not  remain  stationary  upon  the  field  of 
battle  exposed  to  the  fire  of  the  modern  rifle,  machine  gun  and 
artillery. 

Fortifications  therefore,  while  essentially  defensive  in  their 
nature,  will  be  extensively  employed  also  in  the  attack.  The 
neglect  to  utilize  them  will  involve  heavy  losses  and,  if  opposed 
to  a  skillful  adversary,  will  invite  defeat.  On  the  other  hand, 
their  excessive  and  indiscriminate  use  limits  the  mobiUty  of 
the  troops,  tends  to  destroy  the  aggressive  spirit  which  is  es- 
sential to  success,  and  surrenders  the  initiative  to  the  adversary. 
Field  fortifications  then  are  a  means  to  an  end.  If  used  in- 
discriminately, without  due  regard  for  the  strategical  and  tactical 
requirements  of  the  situation,  they  exercise  a  most  baneful  in- 
fluence. Their  correct  employment  for  the  achievement  of 
the  purpose  in  view  calls  for  the  highest  skill  of  the  commander. 
The  technical  details  of  the  works  themselves  are  compara- 


74  THE  ENGINEER  IN  WAR 

lively  simple  and  readily  comprehended,  but  their  location, 
arrangement  and  adaptation  to  the  tactical  situation  and  to  the 
terrain  call  for  a  high  degree  of  skill,  analogous  to  that  required 
in  road  and  railroad  location. 

The  characteristic  features  of  fortifications  in  all  ages  have 
varied  with  the  nature  of  the  weapons  employed  and  with  the 
particular  tactical  object  in  view.  Structures  which  would  pro- 
vide protection  against  arrows  and  stones  would  be  quite  inade- 
quate against  modern  artillery.  The  hasty  outpost  trenches  of 
a  rear  guard  in  retreat  would  be  quite  unsuited  to  an  army  en- 
gaged in  a  protracted  and  decisive  struggle.  In  general  fortifica- 
tions are  designed  to  serve  two  purposes: 

1.  To  facilitate  the  effective  use  of  the  weapons  of  the  defenders;  and 

2.  To  restrict  the  effective  use  of  the  weapons  of  the  attackers. 

All  constructions  which  serve  either  of  these  purposes  may  then 
be  classed  as  field  fortifications  and  will  include  the  following: 

(a)  Rifle  trenches  for  the  firing  line  and  cover  trenches  for  supports. 
(6)  Emplacements  for  machine  guns  and  artillery. 

(c)  Shelters  for  protection  against  fire,  particularly  shrapnel  and  high 
explosive  shells,  and  against  weather. 

(d)  Communicating  trenches  between  supports  and  firing  line. 

(e)  Observing  stations,  dressing  stations,  kitchens  and  latrines. 

if)  Obstacles  to  retard  the  enemy's  advance  and  hold  him  under  fire, 
including  explosive  mines. 

(g)  Demolitions  for  clearing  the  field  of  fire  and  restricting  the  tactical 
maneuvers  of  the  enemy. 

(h)  Measures  for  concealing  all  works  from  the  enemy's  view. 

(t)  Mining  operations  or  tunneling  for  subterranean  advance  against  the 
hostile  works. 

0")  General  communications,  such  as  roads,  foot  paths,  light  railways, 
telegraph  and  telephone  lines,  signal  stations,  etc. 

Most  of  these  works  must  necessarily  be  executed  by  the  com- 
batant troops  who  are  to  occupy  them,  and  all  line  (combatant) 
officers  should  be  qualified  to  superintend  their  construction. 
The  engineers,  however,  will  constantly  be  called  upon  for  ad- 
vice and  assistance  as  to  location  and  details,  and  in  the  execu- 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS         75 

Lon  of  some  of  the  more  difficult  tasks  their  special  training 

d  equipment  will  be  necessary. 

Geographical,  political  and  other  conditions  and  strategical 
lonsiderations  will  determine  the  theater  of  war.     The  position 

be  occupied  and  fortified  will  be  fixed  by  tactical  considera- 

ons.     The  general  line  to  be  occupied  will  usually  be  determined 

om  a  map,  but  the  actual  location  of  the  trenches  and  accessory 

orjcs  can  be  satisfactorily  made  only  on  the  ground. 

These  are  certain  requirements  which  experience  indicates 
ihat  a  defensive  position  and  the  works  executed  thereon  should 

ilfiU.  Many  of  these  requirements  are  at  variance  with  each 
ither  and  it  will  never  be  practicable  to  find  a  single  position 

hich  fulfills  them  all.  Skill  and  experience  are  necessary  to 
[etermine  the  requirements  which  are  of  paramount  importance 
in  any  particular  case.  Often  it  will  be  a  question  simply  of 
making  the  best  of  the  locality  in  which  the  troops  find  them- 
selves. Often  works  hastily  constructed  on  the  field  of  battle 
are  later  elaborated  and  strengthened  to  meet  the  developments 
in  the  tactical  situation  until  the  operations  partake  very  largely 
of  the  nature  of  siege  warfare,  as  is  the  case  today  on  the  western 
battle  front  in  Europe. 

The  matters  to  be  considered  in  selecting  and  organizing  a 
position  are:  The  mission  or  purpose  of  the  command,  their 
numbers  and  quaUty;  strength,  position  and  probable  inten- 
tions of  the  enemy;  the  weapons  possessed  by  both  combatants; 
the  nature  of  the  terrain,  faciUties  for  maneuver  or  retreat; 
whether  delaying  or  decisive  action  is  contemplated;  the  time 
the  position  must  be  held;  the  time  available  for  preparation; 
etc.,  etc. 

The  first  requirement  of  a  defensive  position  is  that  it  shall 
be  one  which  the  enemy  must  attack  to  accompUsh  his  mission. 
If  he  can  attain  his  purpose  without  such  attack,  then  the  position 
is  useless  and  the  time  spent  in  preparing  it  wasted. 

The  following  are  certain  additional  considerations  to  be  given 


76  THE  ENGINEER  IN  WAR 

such  weight  as  the  particular  circumstances  of  the  case  may 
require : 

(a)  Is  it  proper  to  take  up  a  position,  or  does  the  situation  call  for  advance 
or  retreat? 

(6)  Is  the  position  suited  to  the  strength  and  armament  of  the  force  which 
is  to  occupy  it? 

(c)  Is  the  position  to  be  held  indefinitely?     If  not,  for  how  long  a  time? 

(d)  What  are  the  strength  and  intentions  of  the  enemy?  What  weapons 
has  he?     Is  he  provided  with  means  for  aerial  reconnaissance? 

(c)  Are  there  good  positions  with  clear  view  and  field  of  fire  for  both  infan- 
try and  artillery?  Is  there  a  good  field  of  fire  at  all  ranges?  If  not,  which 
is  more  important,  a  near  or  distant  field  of  fire? 

CO  What  are  the  facilities  for  advance  or  retreat  from  the  position. 

(g)  Are  the  flanks  of  the  position  naturally  secure?  If  not,  what  expedi- 
ents may  be  adopted  to  secure  them? 

(h)  Are  the  communications  within  the  position  good? 

(i)  Is  there  cover  for  supports  and  reserves? 

(j)  Does  the  terrain  present  natural  features  adaptable  to  defense,  or  will 
great  labor  be  required? 

(k)  Is  the  ground  in  front  such  as  to  facilitate  the  enemy's  attack?  Are 
there  natural  obstacles  to  his  advance?  Are  any  artificial  obstacles  re- 
quired? 

(0  Is  the  ground  in  rear  favorable  for  counter-attack  in  case  the  enemy 
should  penetrate  the  first  line  of  works? 

(m)  Is  the  position  naturally  concealed  from  view,  including  view  by  aerial 
scouts?     If  not,  what  artifical  means  of  concealment  are  possible? 

(n)  How  much  time  is  available  for  the  preparation  of  the  position? 
How  much  time  will  each  item  of  the  work  require,  and  what  is  the  order  of 
relative  importance?  How  should  the  labor  and  tools  be  distributed  to  pro- 
duce the  best  results? 

Those  and  many  other  important  questions  must  be  considered. 
As  has  been  stated,  a  single  position  giving  a  favorable  reply  to 
all  these  questions  will  never  be  found.  Any  position  must  })e 
a  compromise  between  advantages  and  disadvantages. 

Success  in  battle  is  determined  by  fire  superiority,  without 
which  the  assailant  can  not  advance  and  the  defender  can  not 
hold  his  ground.  Field  fortifications  increase  the  fire  effect  of 
the  troops  occupying  them  and  decrease  the  fire  effect  of  the 
enemy.     They  are  designed  to  afford  the  maximum  protection 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS- 


77 


^■he  defender's  weapons. 

H  The  shelter  best  fulfilling  these  requirements  is  the  simple 
^■ifle  trench  from  which  the  soldier  may  deliver  fire  in  a  comfort- 
H^ble  standing  position  over  a  low  earth  parapet  or  through  a 


RECESSED  ^Sk  TRAVERSED  FIRE  TRENCH 

(no  head  cover) 


SECTION 


Fig.  29. 

loophole  in  the  parapet.  Such  rifle  trenches  are  accordingly  the 
principal  feature  of  field  fortifications  (Figs.  29,  30,  32  and  33). 
The  parapet  is  made  sufficiently  thick  to  resist  penetration  by 
rifle  bullets  or  shrapnel,  which  requires  about  3  ft.  of  ordinary 
earth.  The  parapet  should  be  sufficiently  high  to  afford  a  view 
of  the  foreground  but  in  order  to  be  inconspicuous  it  should  be 


78 


THE  ENGINEER  IN  WAR 


no  higher  than  necessary  for  this  purpose.  Ordinarily  its  height 
will  be  from  9  to  18  in.  above  the  surface  of  the  ground,  unless 
excavation  is  very  difficult  in  which  case  a  shallower  trench  and 
a  higher  parapet  may  be  used.  Such  a  trench  affords  no  ade- 
quate protection  against  direct  hits  by  high-explosive   shell, 


Fia.  30. — Simple   rifle   trench   with   sand-bag  and   hurdle  revetment  and 
splinter-proof  shelters  under  parapet. 

which  would  destroy  the  parapet  and  kill  the  man  behind  it. 
Such  shells  will  also  penetrate  and  demolish  any  shelter  which 
it  is  practicable  to  construct  in  the  field.  The  only  protection 
against  the  fire  of  large  cahber  guns  which  troops  in  field  works 


I 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS 


79 


U 


5-G  5  !»  S 

to     0^  O     u 


t   < 


to     &^  6     o     . 


1S3HQ      lV0IH<iVii9O3Q 


jLsjuo  jt^avini^  I 


80 


THE  ENGINEER  IN  WAR 


enjoy  is  the  improbability  of  direct  hits.  This  probability  is 
so  small  that  under  battle  conditions  it  has  been  found  that  the 
destruction  of  trenches  by  shell  fire  requires  an  expenditure  of 
ammunition  out  of  proportion  to  the  results  obtained.  It  is 
therefore  seldom  attempted.  The  attack  of  such  trenches  will 
be  by  means  of  showers  of  shrapnel  and  rifle  bullets  (Fig.  31). 
While  the  actual  physical  effect  of  such  fire  in  killed  and  wounded 


Fig.  32. — Rifle  trench  with  head  cover  (loopholes)  and  traverses. 

may  not  always  be  great,  it  may  force  the  defenders  to  keep 
their  heads  down  below  the  parapet  and  prevent  reinforcements 
from  coming  up,  and  this  will  diminish  the  volume  and  accuracy 
of  their  fire  and  may  permit  the  attacking  infantry  to  advance 
against  the  trenches. 

To  further  decrease  the  vulnerabiUty  of  the  defenders  the  para- 
pet may  be  provided  with  head  cover  by  placing  in  the  parapet 
loopholes  of  plank,  sand  bags,  etc.  (Figs.  32  and  33).     This  allows 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS 


81 


the-  occupants  to  deliver  fire  without  exposing  their  heads  and 
shoulders  above  the  crest  of  the  parapet.     Overhead  cover,  con- 


FiG.  33. — Rifle  trench  with  phmk  loopholes  and  shelters  under  parapet. 
The  latter  is  being  covered  with  sod  for  concealment. 

sisting  of  a  shelf  of  plank  covered  with  earth  or  steel  plates  sup- 
ported by  framework  may  also  be  provided.     As  this  requires 


Fig.  34. — Rifle  trench  with  overhead  cover. 


considerable  time  and  labor  to  construct  and  greatly  increases 
the  visibiUty  of  the  parapet  as  a  target  it  is  of  limited  applica- 


82  THE  ENGINEER  IN  WAR 

tion  (Figs.  34  and  35).  The  troops  in  the  present  European  war 
are  provided  with  steel  helmets  stout  enough  to  deflect  rifle 
bullets  and  shrapnel  fragments.  Trenches  are  often  provided 
with  overhead  nets  to  stop  grenades. 

The  trenches  are  made  very  narrow  with  steep  side  slopes  in 
order  to  reduce  the  possibility  of  shrapnel  falling  in  the  trench. 
If  the  earth  will  not  stand  naturally'on  a  steep  slope  some  form 


Fia.  35. — Rifle  tn.'iiLii  wiih  ovurhead  cuvt-r  ui  steel  plaUs  &u]jported  on 

frame-work. 

of  revetment  must  be  provided.  The  most  common  forms  are 
planks  or  hurdles  of  woven  brush,  sand  bags,  fascines,  and  tho 
like  (Figs.  36  and  37).  Drainage  must  also  be  provided  if  the 
trenches  are  to  be  occupied  during  rainy  weather.  If  the  trench 
can  be  properly  graded  a  continuous  drain  may  be  carried  alon^ 
the  back  of  the  trench  and  led  out  at  the  lower  end  (Fig.  29). 
Otherwise,  sump  holes  may  be  provided  at  intervals.  Surface 
drains  may  also  be  dug  on  the  high  ground  above  the  trenches. 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS         83 


Fig.  36. — Common  forms  of  revetment. 


84  THE  ENGINEER  IN  WAR 

To  permit  the  movement  of  men  along  the  trench  it  may  be 
widened  and  deepened  at  the  rear,  or  a  separate  trench  parallel 
to  and  immediately  in  rear  of  the  fire  trench  may  be  provided 
(Figs.  30  and  38). 

In  order  to  protect  the  occupants  from  oblique  or  enfilade  fire 
and  to  localize  the  effect  of  shells  bursting  in  the  trench,  banks 
of  earth  perpendicular  to  the  parapet  and  of  equal  or  somewhat 
greater  height  may  be  placed  at  intervals.  These  are  called 
traverses  (Figs.  29  and  32) .  They  should  be  thick  enough  to  resist 
ponotration  by  rifle  bullets  and,  in  order  to  take  up  as  little  room 


Fig.  37. — Common  forms  of  revetment.     Plank,  turf,  sand-bags,  gabions 

and  logs. 

as  possible,  their  sides  should  be  steep,  and  revetted  if  neces- 
sary. They  are  placed  usually  at  intervals  of  one  or  two  squads 
(8  to  16  men)  and  communicating  trenches  are  dug  around  them, 
either  in  front  or  in  roar. 

Bomb-proof  shelters  are  often  provided  in  the  fire  trenches 
for  the  supports  or  for  sheltering  the  occupants  when  not  actually 
firing.  These  consist  generally  of  excavations  under  the  parapet, 
open  to  the  rear.  If  provided  with  a  sufficient  overhead  cover- 
ing of  earth  they  afford  complete  protection  except  from  direct 
hits  by  large  shells  and  grenades  or  shells  bursting  in  the  trench. 
They  are  provided  with  a  roof  of  poles  or  planking.     The  roof 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS         85 

may  be  placed  on  the  ground  and  the  earth  excavated  from  be- 
neath and  thrown  on  top.  A  seat  should  be  placed  at  the  front 
and  the  headroom  should  be  at  least  sufficient  for  a  comfortable 
sitting  posture  (Figs.  29,  30,  33  and  39). 

Concealment  from  the  enemy's  view,  both  before  and  during 
combat,  is  a  most  important  element  of  protection  from  hostile 
fire.  The  freshly  turned  earth  of  a  parapet  is  exceedingly  con- 
-l)icuous,  forms  an  excellent  target  unless  concealed,  and  con- 
si(leral)le  labor  and  skill  may  well  be  employed  to  render  the 
works  inconspicuous.  The  trenches  should  be  kept  off  the  sky  line. 
I  f  necessary  to  place  them  on  a  crest  they  may  be  concealed  by 
shrubbery  or  brush  placed  behind  them.  The  obstacles  in  front 
of  the  trenches  must  be  inconspicuous.  The  first  requirement 
tor  concealment  is  that  the  works  should  be  blended  with  the 
existing  natural  and  artificial  features  of  the  terrain.  The  para- 
pets should  be  low  and  all  sharp  angles,  either  vertical  or  hori- 
zontal should  be  avoided.  If  built  on  the  turf  this  may  be  cut 
in  strips,  rolled  to  the  front  and  rolled  back  over  the  parapet 
when  the  latter  is  completed,  thus  concealing  the  fresh  earth. 
The  parapet  may  be  covered  with  leaves  or  shrubs  naturally 
disposed  and  its  ends  should  be  graded  gently  into  the  natural 
ground.  The  parapet  should  be  sufficiently  high,  however,  to 
conceal  the  rear  lip  of  the  trench.  Loopholes  in  particular  are 
conspicuous  and  should  be  concealed  by  a  shrub  or  branch,  which 
will  ordinarily  not  interfere  with  fire  through  the  hole.  A  low, 
thin  hedge  will  completely  conceal  a  trench  immediately  behind  it 
without  interfering  with  fire.  Works  placed  just  inside  the  edge 
of  a  wood  are  very  difficult  to  distinguish,  but  if  the  edge  of  the 
wood  be  sharply  defined  it  will  itself  afford  excellent  ranging 
points  for  the  hostile  fire.  Diversified  ground,  ravines  and  ridges, 
standing  crops,  scattered  trees,  hedges,  fences,  etc.,  lend  them- 
selves to  the  concealment  of  the  works  and  should  be  utilized  to 
the  utmost.  Skill  in  this  particular  branch  of  landscape  garden- 
ing will  produce  remarkable  results  and,  under  favorable  condi- 
tions,  trenches  may  be  rendered  indistinguishable  even  at  a 


86 


THE  ENGINEER  IN  WAR 


distance  of  100  ft.  If  opportunity  is  afforded  the  works  should 
be  examined  from  the  front,  the  enemy's  point  of  view,  when  the 
best  location,  the  necessity  for  concealment  and  the  measures 
that  should  be  adopted  will  become  apparent.  The  highest 
expression  of  the  art  of  field  fortification  consists  in  utilizing  to 
the  best  advantage  the  existing  natural  and  cultural  features  of 
the  terrain,  both  to  increase  the  effectiveness  of  the  works,  and 
to  insure  that  concealment  which  is  so  important  an  element 
of  security. 

STANDARD     FIELD    TRENCHES 
Firing  Trench 


Fig.  38. — Standard  field  trenches,  showing  communications  between  firing 

line  and  supports. 

The  supports  for  the  firing  line  should  be  placed  as  close  to 
the  latter  as  the  requirements  of  easy  concealment  and  protec- 
tion from  the  enemy's  fire  will  allow.  Natural  cover,  if  available 
within  a  reasonable  distance,  is  to  be  preferred,  both  because  of 
superior  concealment  and  the  lesser  amount  of  labor  required 
in  its  adaptation.  Natural  shelter  also  possesses  the  great  ad- 
vantage that  it  does  not  ordinarily  restrict  the  tactical  mobility 
of  the  troops  to  the  same  extent  as  cramped  and  confined  artificial 
shelters,  difficult  of  ingress  and  egress.  Accordingly,  while  the 
immediate  supports  of  the  firing  fine  must  often  of  necessity  be 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS 


87 


immobilized  in  artificial  shelters,  for  the  mobile  reserves  who  must 
be  ready  for  prompt  concentration  at  the  critical  points,  natural 

I  shelter  well  in  rear  of  the  firing  line  will  almost  invariably  be 
sought; 


Fig.  39. — Shelter  under  parapet  in  construction.     Timber  frame  and  cover- 
mg  of  sand-bags  on  plank. 

A  covering  ridge  just  back  of  a  firing  hne  may  afford  ex- 
cellent natural  cover,  or  may  be  artificially  prepared  with 
little  labor,  but  in  the  absence  of  some  such  natural  feature, 
artificial  cover  must  be  provided.  This  will  usually  consist  of 
trenches  in  rear  of  the  firing  Une.     As  such  trenches  are  not  re- 


f 


88 


THE  ENGINEER  IN  WAR 


quired  to  deliver  fire,  more  complete  protection  to  the  occupants 
is  possible  than  in  the  fire  trenches.  The  trenches  are  usually- 
made  very  deep  and  comparatively  narrow  and  may  be  roofed 
over  or  have  bomb-proof  chambers  leading  out  from  them.  In 
a  position  which  is  occupied  for  some  time  these  chambers  may 
be  developed  into  elaborate  subterranean  barracks,  with  planked 
ceilings  supported  by  columns,  drainage,  water  supply,  artificial 


Fig.  40. — Second  line  of  defense  showing  simple  traversed  trench  and  com- 
municating trench  zig-zag  to  front. 


light  and  heat,  etc.     In  this  manner  hasty  field  fortifications  are 
gradually  developed  into  elaborate  siege  works. 

Commimicating  trenches  must  ordinarily  be  provided  to  allow 
of  a  safe  passage  between  the  support  shelters  and  the  firing  line 
(Figs.  38  and  40).  As  these  trenches  will  be  occupied  only  for  a 
few  seconds  while  passing  to  and  fro,  simple  concealment  from 
view  will  often  be  sufficient.     The  trenches,  however,  should 


FIELD  FORTIFICATION  AND  SIEGE  OPERTAIONS 


89 


mally  approach  a  firing  line  in  a  direction  oblique  to  the  enemy's 
ire,  that  they  may  not  be  subject  to  enfilade,  or  they  may  zig- 
zag to  the  front.     The  parapet  is  placed  on  the  exposed  side.     If 
the  location  of  these  trenches  is  such  as  to  render  them  conspicu- 


Military  iiiiniiig.     The  linings  are  carried  in  stock. 


ous  and  subject  to  fire,  they  may  be  roofed  over  or  a  subter- 
ranean gallery  may  be  substituted  for  an  open  trench. 

Subterranean  attack  has  long  been  characteristic  of  siege 
operations  and  may  also  be  an  important  feature  of  modern  trench 
warfare.     It  is  conducted  by  sinking  shafts  and  driving  sub- 


90 


THE  ENGINEER  IN  WAR 


Fig.  42. — Military  mining.     Linings  for  shafts  and  galleries. 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS         91 


Chevaux-de-frise 


Charge  'of 
Explosive 


Fougasse 


Fig.  43. — Types  of  military  obstacles. 


92 


THE  ENGINEER  IN  WAR 


terranean  galleries  toward  the  enemy's  works.  At  the  end 
of  the  tunnel  a  large  charge  of  explosive  is  set  off,  destroying  a 
section  of  the  enemy's  hne  of  intrenchments  (Fig.  48).  In  the 
confusion  following  the  explosion  an  assault  overground  is  made 
on  the  hostile  works.  Protection  against  this  mode  of  warfare 
is  had  by  means  of  ''listening  galleries"  driven  forward  from  the 
intrenchments.  By  means  of  these  the  enemy's  subterranean 
operations  may  be  detected  and  measures  taken  to  frustrate 
them.  The  excavation  is  made  by  hand  with  specially  con- 
structed tools,  by  the  use  of  hght  charges  of  explosives  or  by 


I'lo.  44. — Barbed  wire  entanglement.     The  soldiers  are  cutting  the  wire 

with  shears. 


boring  machines  operated  bj^  electricity  or  compressed  air. 
Small  trams  may  be  used  to  remove  the  excavated  material  and 
in  long  galleries  artificial  light  and  ventilation  will  be  required. 
The  galleries  are  lined  with  wood  sheathing  as  the  excavation 
progresses  (Figs.  41»and  42). 

If  opportunity  allows,  the  foreground  of  the  works  will  be 
prepared  with  a  view  to  improving  the  field  of  fire  and  embarrass- 
ing the  movements  of  the  enemy.  Trees,  buildings  and  other 
features  which  obstruct  fire  are  removed,   roads  and  bridges 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS 


93 


demolished,  ranges  to  important  points  measured,  etc.  In  this 
work  explosives  are  liheially  employed  to  save  time  and  labor. 
Fire  should  be  used  sparingly  as  it  renders  the  locality  conspicuous 
both  during  and  after  the  conflagration.  Obstacles  of  various 
kinds  arc  placed  in  the  foreground  to  retard  the  enemy's  move- 
ments and  hold  him  under  the  fire  of  the  defense  (Fig.  43). 
Ravines  which  might  permit  concealed  approach  may  be  choked 
l)y  foiling  trees  in  them.  Low  land  may  be  inundated  by  means 
of  dams  in  the  streams.  All  obstacles  should  be  such  as  to  re- 
tard movement  without  affording  cover  from  fire.     The  most 


i'i. 


ALU 


effective  obstacle  is  a  belt  of  wire,  preferably  of  barbed  wire, 
strung  on  posts  or  other  support.  This  is  known  as  a  wire  en- 
tanglement and  is  difficult  to  remove  or  destroy  by  explosives 
(Fig.  44).  It  may  be  effectively  concealed  in  high  grass  or  stand- 
ing crops.  It  should  usually  be  placed  close  in  front  of  the 
trenches  in  order  to  prevent  its  removal  by  the  enemy  and  to 
hold  him  at  the  point  where  the  defender's  fire  is  most  effective. 
Other  favorite  forms  of  obstacles  are  abattis  or  slashings  of 
trees  with  barbed  wire  interlaced,  paUsades  or  picket  fences,  pits 
covered  with  brush,  wire  fences,  chevaux-de-frise,  military  ex- 


94 


THE  ENGINEER  IN  WAR 


plosive  mines  with  charges  of  broken  stone,  and  the  hke  (Figs. 
45,  46,  47  and  48).  As  with  the  trenches,  great  pains  should  be 
taken  to  conceal  these  obstacles  from  the  enemy's  view,  espe- 
cially as  they  may  disclose  the  location  of  the  trenches  in  rear. 
Accordingly  they  should  be  placed  in  the  zone  where  the  de- 
fenders' fire  is  most  effective  since  this  renders  the  obstacles  most 
effective  and  also  makes  it  difficult  for  the  enemy  to  remove  or 
destroy  them.  In  the  presence  of  the  enemy  obstacles  must 
generally  be  placed  and  repaired  under  cover  of  darkness. 

As  the  best  protection  against  hostile  fire  is  concealment  from 
view,  night  attacks  are  of  common  occurrence  in  trench  warfare. 


Fig.  46. — Chevaux-<le-frise  and  wire  entanglement. 


and  to  guard  against  these  artificial  illumination  of  the  battle- 
field by  night  is  essential.  Flares  or  torches  may  be  used  to 
illuminate  the  enemy's  movements,  or  as  warning  signals.  Bon- 
fires may  also  have  a  limited  application.  They  are  often  used 
to  mark  fords  over  streams,  or  to  indicate  areas  where  aviators 
may  make  a  landing.  Such  illuminations,  should  if  practicable, 
be  screened  on  the  side  toward  the  defense. 

Searchlights  are  often  placed  on  the  Une  of  the  fire  trenches, 
but  generally  will  occupy  some  commanding  point,   such  as 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS         95 


Fig.  47. — Fougasse  or  small  land  mine  exploding. 


Fig.  48. — ^Land  mine — 2UU  lbs.  of  dynamite. 


96  THE  ENGINEER  IN  WAR 

a  ridge  or  hillock  in  rear  of  the  line.  Arrangements  should  be 
made  for  moving  them  occasionally  from  place  to  place  since,  if 
fixed  in  one  position,  they  are  liable  to  be  reached  by  hostile  fire. 
Rockets  or  bombs  may  be  used  for  signalling  and  illuminating. 
One  type  of  illuminating  rocket  is  provided  with  a  parachute 
which  will  sustain  the  light  as  long  as  forty  seconds.  Aero- 
planes and  balloons  may  be  fitted  with  searchhghts,  or  may  drop 
illuminating  bombs.  Searchlights  for  use  with  a  mobile  army 
in  the  field  must  be  rugged,  and  of  such  size  and  construction 
that  they  are  readily  transportable.  The  source  of  power  for 
the  field  searchlight  must  also  be  readily  transportable,  other- 
wise its  use  on  the  battlefield  might  seriously  encumber  its 
operators.  In  European  countries  various  types  of  field  search- 
lights have  been  developed.  Some  of  these  are  mounted  on 
motor  trucks,  and  some  are  designed  for  animal  traction.  Ordi- 
narily some  method  is  necessary  for  raising  the  light  so  as  to 
increase  its  effectiveness.  Several  types  of  collapsible  or  tele- 
scoping towers  are  in  use.  If  not  raised  considerably  above  the 
ground,  searchlights  cast  long  shadows  and  illuminate  the  im- 
modiato  foreground  to  an  undesirable  extent.  The  current  re- 
quired for  operating  the  searchlights  may  be  supplied  by  a  gas 
engine  connected  to  a  suitable  generator.  In  many  cases  the 
engine  driving  the  motor  truck  is  made  to  furnish  power  for  the 
searchlight.  Storage  batteries  or  dry  cells  may  be  used  where 
suitable.  Steam  engines  can  be  connected  to  proper  generators, 
but  a  considerable  time  is  necessary  before  the  plant  can  com- 
mence to  furnish  power.  Smoke  from  a  steam  plant  is  also 
objectionable,  as  it  might  disclose  the  location  of  the  plant. 
In  addition  to  electricity,  resort  may  be  had  to  acetylene  or 
other  suitable  gas  for  the  source  of  light. 

Machine  guns  are  employed  in  the  fire  trenches  or  in  specially 
prepared  emplacements  in  the  intervals.  They  are  extensively 
used  to  support  the  line  at  localities  where  infantry  fire  is  re- 
stricted. Artillery  is  usually  placed  behind  the  line  of  infantry 
defense,  natural  cover  being  utihzed  as  far  as  possible  (Fig.  49). 


I 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS 


97 


The  numerous  and  infinitely  various  works  included  under  the 
term  "field  fortifications"  will  usually  be  executed  under  the 
most  trying  conditions.  Frequently  they  must  be  constructed 
actually  under  hostile  fire.  The  details  of  the  works  are  there- 
fore necessarily  simple,  but  this  very  simplicity  is  the  highest  ex- 
pression of  the  skill  of  the  designer,  as  there  is  a  very  great 
tendency  to  over-elaboration.  It  is  to  be  borne  in  mind  that  the 
works  must  ordinarily  be  constructed  by  the  troops  which  are 
to  occupy  them   and  that  of  the  average  untrained  man  little 


Fig.  49. — Emplacement  for  machine  or  field  gun. 

more  than  ordinary  earth  excavation  can  be  demanded.  The 
works  therefore  must  be  designed  for  rapid  construction  by 
unskilled  labor  with  simple  tools  and  the  materials  of  nature. 
These  conditions  and  the  experience  derived  from  meeting  them 
have  resulted  in  the  development  of  certain  type  plans.  These 
plans  are  by  no  means  rigid  but  must  be  infinitely  varied  to  meet 
the  actual  conditions,  such  as  terrain,  nature  of  soil,  tools  and 
materials,  time  available  for  construction,  etc.     Each  situation 

7 


98  THE  ENGINEER  IN  WAR 

is  unprecedented  and  calls  for  new  measures  adapted  to  the 
circumstances.  The  engineer  or  line  ofl&cer  who  directs  the 
work  must  have  a  thorough  knowledge  derived  from  study  and 


Fig.  50. — Detailed  location  of  rifle  trenches. 


experience  of  the  demands  of  the  situation,  the  works  that  will 
be  required,  the  relative  importance  of  the  different  works,  and 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS         99 

the  time  that  will  be  required  to  construct  them.  Without  a 
comprehensive  grasp  of  the  situation  the  works  will  be  poorly 
located  and  badly  adapted  to  the  situation,  and  confusion  in- 
stead of  system  will  characterize  the  operations.  In  the  end, 
unnecessary  bloodshed  and  loss  of  life,  defeat  and  ruin  of  the 
combatant  force,  or  national  disaster  will  be  the  logical  results 
of  incompetence  and  inexperience.  Hasty  fortification  is  one  of 
the  highest  of  the  fine  arts  whose  practice  demands  in  a  super- 
lative degree,  judgment,  skill  and  experience,  and  in  whose  field 
the  novice  and  incompetent  may  wreak  utter  disaster  and  ruin. 
This  map  of  an  actual  piece  of  ground  (Fig.  50)  shows  the 
manner  in  which  rifle  trenches  are  disposed  to  cover  the  ground 
in  front  with  their  fire.  There  are  shown  the  trenches  of  three 
battahons,  with  the  detailed  dispositions  of  the  center  battalion. 
The  enemy  is  approaching  from  the  west,  and  it  will  be  observed 
that  the  fire  trenches  in  a  general  way  occupy  the  convex  faces 
of  knolls  or  noses,  with  their  flanks  curved  back  or  ''refused'* 
to  sweep  the  ravines  intersecting  the  front.  The  support 
trenches  of  the  center  battalion  are  also  indicated — they  are 
close  in  rear  of  the  fire  trenches.  The  trees,  buildings,  and 
other  obstructions  which  interfere  with  fire  are  demolished.  In 
particular  the  loop  of  the  creek  which  protrudes  into  the  fore- 
ground in  the  center  of  the  position  is  an  element  of  weakness, 
because  this  creek  with  the  trees  on  its  bank  affords  a  covered 
or  concealed  approach  for  the  enemy.  Accordingly,  the  trees 
around  this  loop  are  thinned  out  (it  is  not  necessary  to  cut  them 
all)  and  the  debris  is  thrown  into  the  bed  of  the  stream  to  ob- 
struct it  and  prevent  its  use  by  the  enemy.  An  examination  of 
this  map  will  indicate  that  these  trenches  are  carefully  disposed 
to  cover  with  their  fire  all  of  the  ground  in  their  immediate  front. 
Thus  it  will  be  observed  that  the  fire  trenches  of  E.  Co.  of  the 
center  battalion  can  not  cover  with  their  fire  the  very  steep 
(hachured)  slope  in  their  front,  immediately  opposite  the  point 
of  the  loop  in  the  creek.  But  this  ground  is  effectively  covered 
by  the  machine  gun  platoon  (M.  G.  Plat.),  by  part  of  H.  Co., 


100  THE  ENGINEER  IN  WAR 

and  by  the  fire  of  the  southernmost  trench  of  the  next  battaUon 
to  the  north.  Similarly  it  will  be  observed  that  the  trenches 
of  the  center  and  left  (southernmost)  battalion,  are  disposed  to 
sweep  the  ravine  between  their  positions,  after  it  has  been  opened 
up  somewhat  by  thinning  out  the  trees  and  underbrush.  The 
trenches  of  the  northernmost  (right)  battalion  enfilade  or  sweep 
the  two  branches  of  the  creek  in  the  foreground  of  the  battalion's 
position.  Here  the  trees  should  be  thinned  out  to  make  the  fire 
effective. 

SIEGE  OPERATIONS 

Siege  operations  have  been  frequent  in  warfare  since  the  dawn 
of  history,  in  fact  they  antedate  the  invention  of  firearms,  and 
were  conducted  in  the  days  when  the  only  weapons  were  bows 
and  arrows,  stones  hurled  by  catapults,  battering  rams,  etc. 
They  were  formerly  distinguished  from  operations  in  the  open 
field  by  the  extreme  formality  which  characterized  the  procedure 
of  both  combatants.  The  increasing  power  of  modem  firearms 
has  tended  toward  the  obUteration  of  the  sharp  distinction  be- 
tween siege  and  field  operations.  On  the  one  hand  we  find 
permanently  fortified  places  making  extensive  use  of  detached 
forts  and  hastily  constructed  field  works  as  accessories  to  the 
main  defense.  On  the  other  hand  we  see  that  the  intensity  of 
the  fire  of  modern  ordnance  has  forced  troops  operating  in  the 
field  to  resort  to  many  methods  formerly  regarded  as  char- 
acteristic of  siege  warfare. 

Important  localities  whose  strategical  value  can  be  foreseen 
are  still  fortified,  however,  in  times  of  peace.  Such  defensive 
works  are  very  elaborate  and  of  great  strength  and  they  are 
provided  with  every  conceivable  device  and  facility  for  resisting 
attack.  An  assault  upon  them  has  little  prospect  of  success 
unless  the  works  have  been  at  least  partially  demolished,  inas- 
much as  they  present  great  physical  obstacles  and  ^fford  sucli 
thorough  shelter  to  the  defenders  that  it  is  difficult  to  shake  their 
morale  or  diminish  the  effectiveness  of  their  fire  by  means  of 


FIELD  FORTIFICATION  AND  SI^O'ErOFSRATIPN^       101 

rifles,  machine  guns  or  light  field  guns.  The  defenders  will  also 
be  provided  with  ordnance  of  the  most  powerful  types,  they 
will  be  intimately  acquainted  with  the  foreground,  which  is 
specially  prepared  in  advance  to  embarrass  the  attack,  and 
they  will  possess  large  supplies  of  ammunition  and  excellent 
facilities  for  its  storage  and  use.  The  fire  of  the  defenders  and 
tlieir  protection  will  therefore  be  more  effective  than  is  possible 
with  less  formal  preparation. 


Fi(i.   ol.-  Hi 


\  y  artillery  for  the  attack  of  a  fortress. 


Such  fortifications  must  generally  be  thoroughly  demolished 
before  their  defenders  can  be  dislodged,  and  for  this  purpose 
guns  of  large  caliber,  hurling  great  charges  of  explosive  are  re- 
(juired,  coupled  often  with  extensive  mining  operations  such  as 
have  been  described. 

The  first  step  in  the  reduction  of  such  a  fortress,  which  should 
be  carried  out  if  practicable,  will  be  to  cut  off  its  supply  and 
reinforcement  as  well  as  its  communication  with  the  outside 
world,  by  surrounding  the  place  with  a  line  of  troops.     This 


102 


THE  ENGINEER  IN  WAR 


is  called  the  line  of  investment.  It  should  generally  be  drawn 
as  close  to  the  fortress  as  the  efifectiveness  of  the  defender's 
fire  will  permit.  It  is  not  necessarily  continuous,  but  must 
usually  be  fortified.  The  investing  troops  may  have  to  resist 
attack  from  more  than  one  direction,  inasmuch  as  the  enemy  may 
endeavor  to  break  the  investment  by  sorties  of  the  garrison  of  the 
fortress,  or  by  the  attack  of  a  field  army  operating  in  conjunction 
with  the  garrison.  If  the  civil  population  has  not  been  previ- 
ously withdrawn  they  are  compelled  by  the  besieger  to  remain  in 
the  fortress  in  order  the  more  rapidly  to  exhaust  its  food  suppUes. 


Fig.  52a. — Formal  attack  of  a  fortress  by  parallels  and  approaches. 

The  investment  having  been  completed  or  found  imprac- 
ticable, one  or  more  points  of  the  fortress  are  selected  for  the 
formal  attack.  Or  if  the  attacker  is  well  supplied  with  heavy 
ordnance  the  works  may  be  generally  demoUshed  and  rendered 
untenable  by  a  vigorous  bombardment. 

The  points  selected  for  attack  will  be  those  where  the  forti- 
fications appear  to  be  weakest,  where  the  attacker's  fire  may  be 
most  easily  concentrated,  where  the  foreground  is  most  favorable 
for  his  operations,  where  he  is  least  apt  to  be  interfered  with  by 
sorties  or  attacks  from  the  outside,  or  where  the  consequences  of 
success  will  be  most  disastrous  to  the  enemy,  etc.,  etc. 


FIELD  FORTIFICATION  AND  SIEGE  OPERATIONS       103 


The  heavy  guns  are  then  emplaced  and  the  bombardment 
commenced  (Fig.  51).     When  the  defender's  artillery  has  been 


Note:  Ouns  of  batteries  of  the  first  artillery  position  whose  lines  of  Are  (dotted) 
nearly  coincide  with  those  of  batteries  of  the  second  position  are  moved 
forward  and  mounted  in  the  2d  artillery  position. 

Fig.  526. — Formal  attack  of  a  fortress  by  parallels  and  approaches. 


brought  under  control  an  attempt  is  made  to  break  out  an  in- 
fantry trench  as  close  as  practicable  to  the  fortress.  This  is 
called   the    "first    parallel."     Zigzag    approaches    are    pushed 


104  THE  ENGINEER  IN  WAR 

forward  from  the  first  parallel  and  a  second  parallel  is  broken  out. 
To  avoid  as  far  as  possible  the  enemj-'s  fire  this  work  is  usualh^ 
(lone  at  night — all  in  one  night  if  practicable.  Successive  par- 
allels are  thus  established  and  pushed  as  close  to  the  enemy's 
works  as  his  fire  will  permit  (Figs.  52a  and  h).  Meantime  the 
operations  are  covered  and  the  fortress  damaged  as  much  as  pos-. 
sible  by  a  practically  continuous  bombardment.  From  the  last 
parallel  mines  are  xiriven  forward  to  demohsh  the  works.  The 
enemy  will  oppose  these  operations  with  fire,  by  sorties  of  the 
garrison  and  by  countermining  operations  against  the  besieger's 
works.  A  breach  in  the  fortress  having  been  effected  by  bom- 
bardment and  by  mining,  the  besieger  delivers  an  assault  from 
the  last  parallel,  supported  by  the  fire  of  his  artillery. 
The  various  means  for  reducing  a  fortress,  therefore  are : 

(a)  Starvation  as  to  ammunition,  food  supplies,  etc. 

(6)  Demolition  of  the  works  by  the  fire  of  large  caliber  guns  and  by 
mining. 

(c)  Assault  of  the  works  from  a  trench  or  "parallel"  established  as  close  as 
practicable. 

These  methods  may  be  employed  singly  or  in  combination, 
depending  upon  the  strategical  situation,  the  purpose  in  view 
and  the  circumstances  of  the  case.  Successful  assault  will  usually, 
however,  be  impracticable  without  a  previous  bombardment. 


CHAPTER  VII 

MILITARY  DEMOLITIONS 

It  has  been  frequently  remarked  that  war  is  a  game  of  destruc- 
tion, and  demolition  of  material  objects  is  indeed  always  an  im- 


FiG.  53. — Ponton  equipage  used  to  replace  ruined  bridge  span.     (Gennari 

ponton  equipage.) 

portant  accessory  of  tactical  operations.     It  serves  to  hamper  the 
movements  of  the  enemy,  to  frustrate  his  plans  and,  by  the 

105 


106  THE  ENGINEER  IN  WAR 

removal  of  obstacles,  it  facilitates  the  operations  of  our  own  forces. 
Wanton  destruction,  however,  especially  of  objects  which  have 
permanent  and  intrinsic  value  aside  from  possible  miUtary  uses, 
will  never  be  justifiable.  Demolition  on  a  large  scale  (except  in 
emergency)  should  not  ordinarily  be  permitted  without  the  ex- 
press order  of  a  responsible  commander,  as  otherwise  military 
expediency  may  degenerate  into  vandalism.  Also  the  demoli- 
tions should  be  carried  no  farther  than  military  necessity 
demands.  Ill-timed  or  premature  destruction  may  involve 
very  unfortunate  consequences,  and  hardship  may  not  be  imposed 
on  the  inoffensive  civil  population  except  where  necessarily 
incident  to  the  successful  prosecution  of  military  operations. 

As  in  all  the  operations  of  war  so  in  military  demoUtion  there 
is  demanded  adequate  results  in  the  minimum  of  time.  Demoli- 
tion is  the  particular  function  of  the  engineer  troops,  but  as  it 
may  be  required  at  any  time  in  any  part  of  the  theater  of  war, 
all  troops  are  now  equipped  with  demolition  outfits.  These 
outfits  must  necessarily  be  simple,  hght  and  portable  while  capable 
at  the  same  time  of  producing  powerful  effects.  The  means  of 
demolition  best  adapted  to  military  requirements  are  fire  and 
explosives.  The  former  requires  no  equipment,  the  latter  pro- 
vides a  powerful  instrument  of  light  weight. 

Demolitions  are  frequently  accomplished  by  the  fire  of  high- 
explosive  shells  from  large  guns.  Indeed,  for  the  destruction  of 
hostile  fortifications  and  obstacles  protected  by  the  hostile  fire, 
this  will  often  be  the  only  practicable  means.  It  is,  however, 
always  expensive  and  often  uncertain  and  inapplicable.  Where 
it  is  possible  to  judiciously  place  charges  of  explosive,  greater, 
more  certain  and  more  prompt  results  can  usually  be  obtained. 

The  advances  made  in  recent  years  in  the  manufacture  of  high 
explosives  have  placed  a  powerful  weapon  in  the  hands  of  the 
military.  But  knowledge  and  experience  in  the  effective  practical 
use  of  explosives  is  not  common  and  it  is  very  important  that  all 
officers,  and  especially  engineer  officers,  should  be  fully  instructed 
in  practical  demolition. 


MILITARY  DEMOLITIONS  107 

An  explosive  for  military  demolitions  should  be: 

(a)  Stable  for  long  periods. 

(&)  Unaffected  by  ordinary  variations  of  moisture  and  temperature. 

(c)  Not  unduly  sensitive  to  shock  in  handling,  transportation,  etc. 

(d)  Not  unduly  difficult  to  detonate. 

(e)  Quick  enough  to  give  good  results  even  when  unconfined. 

(/)  Convenient  in  form  and  consistency  for  transportation  and  use  under 
field  conditions. 

These  requirements  call  for  a  high  explosive  of  medium 
strength,  solid  in  consistency,  and  put  up  in  damp-proof  packages 
of  standard  size.  A  number  of  commercial  explosives  meet 
these  requirements  fairly  well,  and  none  is  invariably  preferred 
to  the  exclusion  of  all  others.  It  will  be  a  question  usually  as  to 
which  can  be  most  readily  obtained  in  sufficient  quantity. 
Amongst  these  explosives  are  gun-cotton,  nitro-glycerine,  dyna- 
mite, trinitrotoluol,  melinite,  lyddite,  shimose,  jovite,  the 
picrates,  fulminates,  Sprengel  safety  mixtures,  gunpowder. 
Dynamite  is  the  most  common  commercial  explosive  in  this 
country  and  is  well  adapted  to  military  uses.  Nitro-glycerine 
is  dangerous  in  handling  and  transportation  because  of  its  liquid 
form.  The  fulminates,  in  particular,  mercury  fulminate,  are 
especially  useful  as  detonators  for  other  explosives  because  of  the 
abruptness  and  violence  of  their  action.  They  are  accordingly 
extensively  used  for  caps,  primers,  etc. 

Explosion  is  produced  by  detonation,  for  which  purpose  a  small 
cap  or  primer  of  fulminate  is  inserted  in  the  charge.  The  cap  may 
be  fired  by  means  of  a  powder  fuse  or  by  electricity.  The  latter 
is  the  preferred  method,  but  requires  a  magneto-electric  exploder 
and  lead  wires.  If  these  are  not  available  the  fulminate  may  be 
ignited  by  means  of  a  powder  fuse.  Two  classes  of  fuse  are 
employed  known  as  time  and  instantaneous.  They  are  dis- 
tinguished by  the  color  of  their  wrappings.  Time  fuse  burns  at 
the  rate  of  about  3  ft.  per  minute;  instantaneous  fuse,  120  ft. 
per  second  or  more.  Caps  and  fuse  must  be  kept  away  from  other 
explosives. 


108  THE  ENGINEER  IN  WAR 

Charges  should  be  tamped  in  some  manner  whenever  this  is 
practicable,  as  their  effect  is  thus  greatly  increased.  Timbers 
j5hould  be  bored  to  receive  the  charge  when  practicable.  Charges 
placed  to  destroy  concrete,  steel,  etc.,  should  be  tamped  with 
earth  or  mud.  If  tamping  is  impracticable  the  charges  must 
be  increased.  Skill  in  placing  the  charge  will  greatly  increase 
its  effect.  Several  small  charges  judiciously  distributed  will 
often  produce  better  results  than  one  large  charge,  but  care  must 
be  taken  to  insure  simultaneous  detonation. 


Railroad  track  cut  by  dynamite. 

In  the  case  of  an  important  demolition  a  reconnaissance  or 
examination  should,  if  practicable,  be  made  to  determine  the 
extent  of  the  destructibn  required  and  the  easiest,  surest  ancf 
most  expeditious  manner  of  accomplishing  it  with  the  men  and 
quipment  available.  The  damage  inflicted  should  be  sufficient 
lur  the  purpose  in  view  and  no  more.  Thus,  if  the  purpose  is 
merely  to  delay  for  a  short  period  the  use  of  a  certain  bridge  it 
may  be  sufficient  to  remove  the  deck  instead  of  destroying  the 
trusses.     A  telegraph  line  may  be  temporarily  interrupted  by 


MILITARY  DEMOLITIONS 


109 


cutting  the  wires,  but  for  complete  demolition  the  poles  should 
be  cut  down  and  burned. 

A  structure  that  is  to  be  demolished  should  be  attacked  at 
its  weakest  point,  or  the  point  where  the  least  time  and  effort  in 
the  way  of  demolition  will  require  the  greatest  time  and  effort  to 
repair  the  damage.  Thus  in  the  case  of  railroads,  which  are 
frequently  attacked,  it  is  easier  to  demoUsh  a  bridge  than  to  tear 
up  track,  but  it  is  much  more  difficult  to  repair  the  damage  in 


Fig.  55. — Rail  "cut  by  5  oz.  of  gun-cotton. 


the  former  case.  It  is  as  easy  to  remove  a  rail  on  a  curve  as  on 
a  tangent,  but  it  takes  more  time  to  prepare  and  place  a  curved 
rail. 

The  proper  charges  of  explosives  to  accompHsh  certain  results 
have  been  determined  by  experiment  and  are  given  in  the 
manuals.  They  serve  as  a  useful  guide  but  can  not  entirely  take 
the  place  of  experience  and  good  sense. 


no 


THE  ENGINEER  IN  WAR 


The  following  notes  will  indicate  the  methods  employed  in 
some  of  the  important  military  demolitions. 

All  timber  structures  may  be  destroyed  by  fire.  For  rapid 
work  they  may  be  sprinkled  with  coal  oil,  tar,  or  other  inflam- 
mable liquid  before  ignition.  Framed  structures  of  wood  or 
steel  may  be  destroyed  by  attacking  the  weakest  members  of 
the  framing.  Thus  in  a  truss  bridge  the  chords  may  be  cut  at 
their  thinnest  points.     Bridges  are  most  effectively  demolished 


Tig.  oO.      M.ici.i;;c  t:;;.ijlu^  l;1  :y,   li.u  lluociiiii^i  iui  Uaiiiiji,  up  ruutls. 

by  overthrowing  their  piers  or  abutments,  which  wrecks  the  entire 
structure  (Fig.  53).  The  most  vulnerable  points  of  roads  and 
railroads  are  the  important  bridges  or  viaducts.  Railroads  may 
also  be  attacked  at  culverts  and  tunnels.  If  these  vulnerable 
points  can  not  be  reached,  railroads  may  be  interrupted  by 
removing  rails  or  cutting  them  with  explosives,  preferably  on 
curves  (Figs.  54  and  55) .  A  fire  is  made  of  the  ties,  the  rails  placed 
therein  and  twisted  while  hot.  An  entire  section  of  track  may 
be  removed  by  opening  the  joints  at  each  end,  loosening  the 


MILITARY  DEMOLITIONS 


111 


ballast  and  then  overturning  the  section.  It  is  best  to  select 
an  embankment  and  throw  the  loosened  section  down  the  slope. 
Railroads  may  be  crippled  by  removing  or  wrecking  the  rolling 
stock,  especially  locomotives,  by  demolishing  switches  and  water 
tanks.  It  is  generally  better  to  wreck  the  road  at  several  points 
rather  than  to  concentrate  the  work  of  destruction  in  one  locality. 


Fig.  57. — Tree  cut  by  necklace  of  2}^  lbs.  of  dynamite. 

Highways  are  very  difficult  to  destroy,  but  the  passage  of  vehicles 
may  be  interrupted  by  digging  trenches  across  them,  by  firing 
land  mines  in  the  surface,  or  filUng  deep  cuts  with  debris  (Fig.  56). 
Buildings  may  be  demolished  by  closing  all  openings  and  firing  a 
large  charge  in  a  central  position.  Telegraph  lines  may  be  in- 
terrupted by  cutting  the  wires,  but  for  complete  demoUtion  the 


112  THE  ENGINEER  IN  WAR 

poles  should  be  cut  down  and  burned,  which  also  destroj^s  the 
cross  arms  and  insulators.  At  stations  the  instruments  are 
removed  or  demolished  and  the  records  seized.  Woods  are 
rendered  useless  as  cover  by  fire  or  by  cutting  down  the  trees 
with  tools  or  explosives  (Fig.  57)  lopping  off  the  branches  and 
throwing  them  into  ravines.  The  trunks  may  be  left  on  the 
ground  and  it  is  neither  necessary  nor  practicable  to  remove  the 
stumps,  as  it  takes  too  much  time.  Masonry  arches  may  be 
attacked  by  explosives  at  the  haunches  or  crown.  In  a  multiple 
arch  bridge  the  destruction  of  a  pier  involves  the  two  adjacent 
arches.  Locks  are  rendered  useless  by  destroying  the  gates  or 
filling  valves.  Supplies  and  materials  of  all  kinds  are  ordinarily 
destroj'ed  by  fire,  after  sprinkling  them  with  inflammable  liquid, 
or  mixing  inflammable  and  non-inflammable  materials. 

Obstacles  placed  in  front  of  trenches  are  very  difficult  to 
destroy  because  they  are  deliberately  constructed  with  that  end 
in  view  and  are  under  the  fire  of  the  defenders  of  the  trenches. 
They  are  often  demohshed  by  shells  and  grenades,  but  such 
methods  are  slow,  expensive  and  unsatisfactory.  Wire  en- 
tanglements are  the  most  effective  of  all  obstacles  and  the  most 
difficult  to  destroy.  They  may  be  cut  with  nippers  (Fig.  44) 
under  cover  of  darkness  or  behind  a  steel  shield.  The  process 
will  usually  be  accompanied  by  heavy  loss  of  life.  Often  it  will 
be  better  to  bridge  over  the  obstacle  with  bundles  of  brush, 
hurdles,  planks,  sections  of  board-walk  specially  prepared,  etc. 

The  use  of  explosives  in  attacking  the  enemy's  works  has  been 
noted  under  "Field  Fortifications." 


CHAPTER  VIII 

MILITARY  RECONNAISSANCE,  SKETCHING  AND 
SURVEYING 

Maps  of  and  information  concerning  the  theater  of  war  have 
always  been  prime  requisites  to  the  successful  conduct  of  military 
operations.  In  these  times,  when  the  combatant  forces  are 
numbered  by  millions,  when  the  theater  of  war  may  embrace 
an  entire  continent,  and  when  troops  may  be  transported 
hundreds  of  miles  in  a  single  day,  the  need  of  complete  and 
accurate  maps  and  information  is  of  far  greater  importance 
than  in  the  past  when  military  operations  were  more  restricted 
as  to  numbers  engaged  and  area  covered.  It  will  be  evident 
that  the  commander  can  not  now  view  the  entire  field  of  conflict 
nor  follow  the  progress  of  events  except  as  portrayed  on  a  map. 
The  modem  game  of  war  then  is  played  upon  a  map  (Fig.  58). 
On  a  table  in  his  tent  or  office  the  strategist  records  and  watches 
the  ever-changing  situation  and  plans  the  movenients  of  troops 
many  miles  away.  In  the  conduct  of  war  the  commanders  are 
dependent  on  their  maps,  and  errors  in  the  maps  have  often 
worked  great  mischief.  McClellan's  advance  on  Richmond  in 
the  Civil  War  met  its  first  serious  check  at  the  lines  on  the 
Warwick  River.  McClellan's  maps  showed  the  stream  parallel 
to  his  line  of  advance,  and  he  regarded  it  as  no  obstacle.  As  a 
matter  of  fact  the  stream  ran  across  the  Peninsula  and  was  found 
to  be  strongly  fortified  by  the  Confederates,  greatly  to  McClellan's 
surprise  and  discomfiture.  The  simplest  scouting  expedition 
or  reconnaissance  requires  a  map  for  its  rapid  and  successful 
prosecution,  and  its  report  to  be  intelligent  must  be  accompanied 
by  a  map  or  sketch.  Each  outpost,  each^camp,  each^march  is 
8  113 


114  THE  ENGINEER  IN  WAR 

made  by  aid  of  and  recorded  and  reported  on  a  map.  Each 
section  of  a  line  of  defense  must  be  mapped,  the  enemy's  disposi- 
tions, movements  and  works  are  reported  by  means  of  maps  and 
sketches.  It  is  therefore  absolutely  essential  that  all  officers 
from  the  highest  to  the  lowest  should  be  able  to  read  a  map 
and  also  to  make  one.  The  duty  of  mapping  will  fall  especially 
upon  the  engineers.  It  is  incumbent  upon  them  to  collect, 
amplify  and  bring  up  to  date  all  existing  maps  and  to  arrange  for 


Fig.  58. — The  modern  game  of  war  is  played  on  a  map. 

their  reproduction  and  distribution.  And  the  lion's  share  of  the 
mapping  to  be  done  during  the  course  of  the  campaign  will  fall 
to  their  lot.  The  engineer  officer  must  be  able  to  make  a  map 
on  foot,  from  an  automobile,  an  aeroplane,  or  on  the  back  of  a 
horse.  He  must  be  able  to  sit  on  a  hill  and  map  the  country  in 
front  of  him,  estimating  the  distances  and  sensing  the  topograph- 
ical features  which  he  can  not  see. 


MILITARY  RECONNAISSANCE  115 

Accurate  maps  require  much  time  and  skill  for  their  prepara- 
tion. If  they  are  not  available  in  advance  of  hostilities  the  army 
must  prepare  its  own  maps  of  the  theater  of  operations  under 
war  conditions.  This  will  delay  and  hamper  their  operations, 
both  because  time  will  be  required  to  prepare  the  maps,  and 
because  maps  produced  under  such  conditions  must  necessarily 
be  rather  crude  and  inaccurate.  Accordingly  the  preparation  or 
collection  in  time  of  peace  of  accurate  maps,  suitable  for  military 
use,  of  all  possible  theaters  of  war  is  an  essential  part  of  any 
scheme  of  national  defense.  Commanders  have  frequently  been 
compelled  to  conduct  campaigns  without  good  maps  prepared  in 
advance,  but  it  is  certain  that  they  were  thus  greatly  handicapped. 

There  is  much  of  our  own  country  which  has  not  as  yet  been 
accurately  surveyed,  and  of  Mexico,  Central  and  South  America, 
and  the  Orient,  we  possess  no  satisfactory  maps.  The  best 
available  maps  for  military  purposes  are  those  of  the  U.  S.  Geo- 
logical Survey.  In  time,  this  survey  will  cover  the  entire  country 
and  will  form  an  important  item  of  our  scheme  of  preparedness, 
but  at  present  much  remains  to  be  done. 

The  scale  of  the  maps  is  a  matter  of  great  importance,  and  for 
military  uses  maps  on  various  scales  will  be  required.  For 
strategical  operations  over  a  considerable  area  small  scale  maps 
will  be  needed.  These  of  course  can  not  exhibit  topography  in 
detail,  but  only  the  more  important  strategical  features,  such  as 
rivers,  mountains,  main  highways  and  railroads,  important  cities, 
fortifications,  etc.  Useful  scales  for  strategical  purposes  vary 
from  about  }4  ^^-  to  the  mile  to  10  miles  to  50  miles  to  the  inch. 
If  such  maps  are  not  available  in  suitable  form  at  the  outbreak  of 
hostilities  they  must  be  prepared  by  a  compilation  of  miscellane- 
ous and  often  discordant  data.  Errors  in  the  important  distances 
may  be,  to  some  extent,  eliminated  by  astronomical  observations 
in  the  field.  For  tactical  purposes  maps  must  be  on  a  scale 
sufficiently  large  to  portray  topographical  details,  yet  not  too 
large  for  convenient  use  in  the  field.  Experience  indicates  that 
a  scale  of  1  in.  to  the  mile  fulfills  these  requirements.     The 


116  THE  ENGINEER  IN  WAR 

Geological  Survey  maps  are  on  a  scale  of  1 :  62,500,  which  is  ap- 
proximately 1  in.  to  the  mile  (12  X  5,260  =  63,360).  The  map 
executed  by  the  military  sketcher  in  the  field  for  use  in  conjunc- 
tion with  the  1  in.  maps  will  vary  from  1  to  3  in.  to  the  mile 
for  road  sketches,  and  from  3  to  6  in.  to  the  mile  for  position  or 
area  sketches. 

It  is  certain  that  in  any  military  operations  in  which  the 
United  States  may  engage,  extensive  surveying  and  mapping, 
both  on  a  small  and  on  a  large  scale  will  be  required  subsequent 
to  the  outbreak  of  hostilities.  Even  if  maps  are  available  in 
advance  they  will  often  be  on  too  small  a  scale  to  meet  all  tactical 
requirements,  they  will  not  portray  all  features  of  military  im- 
portance and  will  not  be  up  to  date.  When  the  surveys  can  be 
executed  under  cover  of  the  first-line  troops  the  methods  for 
mapping  will  be  based  upon  those  employed  in  time  of  peace, 
except  that  refinements  and  hair  splitting  accuracy  will  be 
relegated  to  the  background  and  speed  will  become  paramount 
— as  in  all  mihtary  engineering.  The  control  will  be  established 
by  astronomy,  triangulation,  traverse  and  extensive  /leveling. 
The  filling  in  will  be  done  chiefly  by  the  methods  of  individual 
military  sketching.  On  such  surveys  many  of  the  great  number 
of  civilian  surveyors  in  the  United  States  may  be  usefully  em- 
ployed, if  under  the  direction  of  engineer  officers  who  appreciate 
military  requirements  and  understand  military  methods. 

In  survey  work  executed  with  the  fighting  forces  at  the  front 
quick  results  will  invariably  be  demanded,  and  must  generally 
be  obtained  with  such  simple  instruments  as  can  be  conveniently 
carried  on  the  person  of  the  topographer,  or  with  no  instrument 
at  all.  These  conditions  have  resulted  in  the  adoption  of  instru- 
ments and  methods  which  are  characteristically  military.  While 
a  number  of  methods  are  employed  that  most  commonly  used  is 
a  crude  and  hasty  adaptation  of  the  plane  table  method  of 
surveying  in  which  the  skill  and  experience  of  the  topographer 
must  compensate  for  the  lack  of  time  and  accurate  instruments. 

The  military  plane  table  consists  of  a  small  board,  12  in.  X  14 


MILITARY  RECONNAISSANCE 


117 


in.  in  size  or  less,  which  is  held  against  the  body  of  the  sketcher  or 
mounted  on  a  light  portable  tripod  (Figs.  59  and  62).  The  board 
is  leveled  by  eye  oi:  by  a  small  spirit  level  placed  on  the  board  or 
attached  to  one  of  its  edges.  It  is  oriented  by  means  of  a  compass, 
which  may  be  in  a  separate  case,  or  may  consist  merely  of  a  de- 
clinator attached  to  the  edge  of  the  board.  The  alidade  is  a 
small  flat  ruler  with  folding  sights,  or  more  commonly,  a  simple 


Fig.  59. — Military  plane-table  or  sketching  board,  with  attached  needle  or 
declinator,  three  cornered  ruler  and  tripod. 

three-cornered  piece  of  wood,  the  sights  being  taken  along  its 
upper  edge.  The  horizontal  position  of  points  is  determined 
by  intersection  and  resection,  by  laying  off  the  directions  and 
measuring  the  distances,  etc.  Distances  are  measured  usually 
by  pacing  and  counting  with  a  "tally"  (Fig.  60)  also  by  a  speed- 
ometer, or  an  odometer  on  the  wheel  of  a  vehicle,  by  the  "  walks  " 


118 


THE  ENGINEER  IN  WAR 


of  a  horse,  or  by  time  at  a  known  gait,  either  afoot,  in  a  vehicle, 
or  on  horseback.  In  some  cases,  especially  in  "place  sketch- 
ing," where  the  sketcher  can  not  occupy  the  ground  he  is  to  map, 
distance  may  be  determined  by  some  form  of  simple  range  finder, 
by  angles  measured  with  a  pocket  sextant  (Fig.  60)  or  compass 
from  the  ends  of  a  known  base  (intersection)  and  for  short 
distances  by  estimation.  The  sketcher  will  construct  the 
necessary  scales  of  paces,  wheel  revolutions,  or  time.     If  the 


Fig.  60. — Some  instruments  employed  in  military  sketching, 
sextant,  pace-tally  and  clinometer. 


Pocket 


length  of  his  own  stride  or  the  gait  of  his  horse  has  not  bee 
determined,  this  will  be  done  by  several  pacings  of  a  know 
distance  on  average  ground.  The  scales  are  laid  out  on  paper 
and  pasted  to  the  edges  of  the  ahdade.  Horizontal  angles  are 
laid  off  by  compass  or  alidade  sights  or  in  some  cases  measured 
with  a  pocket  sextant  and  laid  off  with  a  protractor. 

Absolute    elevations   are   determined    with    a    small   pocket 
aneroid.     Slopes  are  measured  by  sighting  along  an  edge  of  the 


\ 


MILITARY  RECONNAISSANCE 


119 


sketching  board,  held  in  a  vertical  plane,  and  reading  the  slope 
by  means  of  a  plumb  line  and  graduations  on  the  lower  edge  of 
the  board  (Fig.  61).  They  may  also  be  measured  by  a  simple 
hand  cHnometer,  such  as  the  Abney,  with  which  very  close  re- 
sults are  obtained  by  a  skilled  operator  (Fig.  60).  The  sketcher 
will  be  provided  with  a  set  of  scales  of  "map  distances."  A 
"map  distance"  is  the  horizontal  map  interval  between  contours. 


(!^=Hl   ^ 

)                    o 

^iZk 

E 

// / / il 1 1 }  il 1 1 1 il\i\ 

Il  Mih  \\\\\\\\ 

C 

Fig.  61. — Measuring  vertical  angles  or  slopes  with  sketching  board. 


It  varies  with  the  scale  of  the  map,  the  vertical  interval  be- 
tween contours,  and  the  slope  of  the  ground.  As  the  first  two 
are  fixed  the  map  distance  varies  with  the  slope,  and  the  scales 
indicate  the  map  distances  or  horizontal  intervals  between 
contours  for  various  slopes.  Having  measured  a  slope  the 
number  and  position  of  the  contour  points  is  determined  by 
applying  the  map  distance  scale  for  that  slope,  no  computation 


120  THE  ENGINEER  IN  WAR 

being  necessary.     If  the  slope  is  not  uniform  the  contour  points 
are  adjusted  by  eye,  but  their  number  is  fixed  by  the  scale. 


Fig.  62. — Military  sketching  (mapping)  equipment  in  case.  Sketching 
board  with  declinator,  scales  of  map  distances,  slope  scale  and  paper  clamps; 
tripod;  prismatic  compass;  clinometer;  stop-watch;  alidade;  pads,  pencils, 
etc. 

Elevations  thus  determined  may  be  checked  with  hand  level 

(or  the  clinometer  set  for  zero  slope)  and  aneroid  barometer. 

In  order  to  facilitate  the  reading  of  maps  those  in  our  service 


MILITARY  RECONNAISSANCE      '  121 

are  constructed  on  what  is  known  as  the  normal  system.  In 
this  system  the  V.I.  between  contours  varies  inversely  as  the 
scale  or  representative  fraction.  Thus  for  a  map  whose  scale 
is  1  in.  =  1  mile,  the  V.I.  is  GO  ft.  for  a  map  whose  scale  is 
3  in.  =  1  mile,  the  V.I.  is  20  ft.  Accordingly,  a  certain  map 
distance  corresponds  to  a  certain  ground  slope,  whatever  the 
scale  of  the  map,  which  greatly  facihtates  the  interpretation  of 
ground  forms  as  portrayed  on  maps  of  various  scales. 

The  method  of  procedure  in  making  such  maps  is  to  determine 
as  accurately  as  practicable,  by  the  methods  aboye  described,  the 
true  horizontal  position  and  elevation  of  a  number  of  critical 
points  in  the  terrain  and  then,  using  these  as  a  skeleton  or 
control,  to  fill  in  the  intervening  topography  by  eye.  The 
speed  with  which  such  a  map  can  be  made  and  its  accuracy 
when  completed  will  depend  very  largely  on  the  skill  of  the 
sketcher  in  selecting  and  locating  the  critical  and  prominent 
points  of  the  terrain  which  will  be  of  use  to  him,  in  selecting 
stations  affording  gootl  views  of  as  large  areas  as  possible,  and 
in  estimating  intermediate  distances  and  slopes  and  interpret- 
ing ground  forms.  The  valley  or  stream  lines  and  the  hills  and 
ridges  form  the  natural  skeleton  for  a  topographical  sketch. 
If  the  position  of  the  stream  lines  and  two  or  more  elevations  on 
same  be  determined,  together  with  the  position  and  height  of 
the  adjacent  knolls  and  ridges,  the  topography  is  readily  sketched 
in  by  eye.  If  the  sketcher  has  skillfully  selected  and  determined 
the  controlhng  elevations  and  distances  the  chance  of  cumulative 
errors  is  greatly  reduced  and  the  sketched  in  topography  may 
compare  favorably  in  accuracy  with  a  painstaking  instrumental 
survey.  Skill  in  such  work  is  attained  only  by  practice.  The 
greater  the  skill  the  smaller  the  number  of  controlling  points 
that  will  be  required.  If  the  sketcher  is  a  proved  adept  at  esti- 
mating slopes  and  distances  he  can  dispense  with  many  of  the 
careful  measurements  which  the  novice  would  be  forced  to 
make. 

Care  should  be  taken  to  avoid  cluttering  the  map  with  details, 


122 


THE  ENGINEER  IN  WAR 


but  it  must  nevertheless  exhibit  all  features  that  are  of  miUtary 
importance.  The  conventional  signs  employed  are  few  and 
simple  (Fig.  63).  Extensive  wooded  or  cultivated  areas  may  be 
designated  by  tracing  their  outline  and  noting  the  nature  of  the 
growth,  as — "shocked  corn,"  "standing  wheat,"  "open  wood," 


I  I  I 


-•— t-     single  Track  R.R. 
1— f    Double  Track  R.B. 


iH3 


iN* 


vX^!y6<rXvvCviv 


Woodfen  Kins  Post  Bridge 
21  Ft.Span,  13  PUDeck. 
10  Ft.abore  Water 

TroM  t.  Suspension  Bridges 
Ford.  3  Ft.I>eep 


Wire  SnUnglement 


^ — o 0 o— o 

9  Shocked  Corn| 


Demolltioa 


Onltirated  Land 


o  e  e  e  e  e 

O    e   O   e   O  e   Orchard 

o  e  o  e  e  o 


•O  •    •    O  O    Open  Woods 

*0    O    *•    e       Site  of  Circle  Indicate! 

e     o  e     •      •     BizeofTreet 


O  o 


JiL-«-i»-.0. 

.«.-«-     .9. 


J9. 


Rough  Symbol  for  Woods 


Woods  with  Undergrowth 


|a.H.|  |c.aj    School.house.Oonrt-hooae 

^1  Masonrjr  Building 

OO  Frame  Building 


-X — y — K — x~  Barbed  Wire  Fence 

_o — o — o — o—  Common  Wire  Fence 
t      t — I      I 

o     0 ^ o_  Main  Road 

— o — o— o — o—  with  Plain  Wire  Fence  on 

both  Sidei 

m"Jl~11Zri  Unimproved  Road 

Trail 

J  T  T  TeleRraph  Line 


Fia.  63. — Conventional  signs  employed  in  military  sketching. 


etc.  Notes  should  describe  the  nature  of  roads,  as — "good 
macadam,  16  ft.,"  "good  earth,  12  ft.,  ditches,"  etc.  The 
span,  width  of  deck,  height,  material  and  practicable  load 
of  bridges  is  indicated  by  notes.  Buildings  are  never  drawn  to 
scale,  but  the  size  and  construction  of  important  buildings  may 


11x14 


1000 


Adams  Q 


Scale  3 1  nches  =1 M  ile 
0      12     3     4      5     6      7      8     9     10    11   12    13    14     15  1600  Yds. 

I       I       I       I       I       I       I       I       I       I       I  — '       ' — =« 1 


H 


H 


1  Mi. 


(123)  Fig.  64. — Road  sketch  executed  by  military  methods. 


Scale  4  Inches -1  Mile.     V.  I.  15  Feet 

Fig.  65. — Position  sketch  executed  by  military  methods. 


1500  Yard:! 


(124) 


MILITARY  RECONNAISSANCE 


125 


be  indicated  by  a  note.  Fords  are  designated  by  noting  width, 
depth  and  velocity  of  stream,  nature  of  approaches  and  bottom. 
The  names  of  railroads,  gauge,  number  of  tracks,  location  and 
capacity  of  stations,  sidings,  water  tanks,  the  rolling  stock  avail- 
able, etc.,  are  noted,  as  also  the  names  and  distances  of  adjacent 
stations  in  both  directions,  the  vulnerable  points  of  the  road, 
such  as  large  bridges,  tunnels,  etc.  Telegraph  and  telephone 
lines  are  of  special  importance,  the  adjacent  towns  to  which  they 


Fig.  66. — Military  ski-tclKTs  wiih  ('(ini])!!!!'!!!. 

lead  should  be  ascertained  by  inquiry.  Streams  which  are  to  be 
used  for  water  supply  may  be  roughly  gauged.  Ground  suitable 
for  camp  sites  or  defensive  positions  should  be  noted,  etc. 
The  local  resources  in  the  way  of  crops,  animals,  foodstuffs, 
tools,  machinery,  etc.,  should  be  ascertained  approximately. 
Towns  are  described  by  giving  their  populations,  nature  of  in- 
dustries, stock  and  output  of  mills  and  factories,  important  build- 
ings, railroads,  telegraph  and  telephone  communications,  etc. 
There  is  hardly  a  local  feature  which  may  not  be  of  importance 


126  THE  ENGINEER  IN  WAR 

from  a  military  point  of  view.  The  reconnaissance  will  generally 
be  for  the  purpose  of  investigating  certain  particular  conditions, 
but  even  under  such  instructions  very  important  matters  out- 
side of  the  instructions  should  be  reported.  The  officer  charged 
with  such  duty  must  have  his  powers  of  observation  and 
acquisitiveness  developed  to  a  high  degree. 

By  the  methods  herein  outlined  a  competent  sketcher  may 
map  ten  or  more  miles  of  road  per  day,  sketching  in  also  the 
topography  on  each  side  which  is  visible  from  the  road.  In 
sketching  an  area  he  may  cover  from  J^  to  2  sq.  miles  in 
a  day,  depending  upon  his  skill  and  the  nature  of  the  terrain 
(Figs.  64  and  65).  Where  an  extensive  area  is  to  be  surveyed 
the  work  is  divided  into  a  number  of  small  areas,  with  natural  or 
artificial  hnes  of  division,  which  are  mapped  simultaneously 
(Fig.  66).  A  number  of  these  area^  will  be  in  charge  of  a  principal 
sketcher  whose  duty  is  to  distribute  his  subordinates,  fixing  the 
hmits  assigned  to  each.  He  makes  certain  that  each  individual 
sketcher  connects  with  his  neighbor  on  either  flank  by  having 
one  or  more  points  in  common,  without  overlapping  or  dupHcat- 
ing  work  further  than  is  necessary  to  join  the  two  sketches  in 
one.  He  carries  an  aneroid  barometer  with  which  he  gives  each 
sketcher  the  elevation  of  his  starting  point.  He  may  be  ac- 
companied by  an  assistant  who  measures  the  distances  and 
sketches  the  important  features  along  the  base  hne  from  which 
the  area  sketchers  start.  This  is  used  later  to  combine  and  co- 
ordinate the  individual  sketches.  These  are  turned  in  simul- 
taneously and  are  pieced  together  and  retraced  or  otherwise 
prepared  for  reproduction.  As  the  sketches  are  usually  made  on 
translucent  vellum  they  maj^  be  printed  directly. 

Mapping  operations  on  a  large  scale  will  ordinarily  involve 
the  correction,  amplification,  compilation  and  reproduction  of 
maps,  and  this  duty  will  fall  to  the  Engineer  Department.  So 
far  as  possible  it  should  be  done  in  the  office,  away  from  the 
haste  and  confusion  of  the  field.  But  much  of  this  work  must 
necessarily  be  done  in  the  field,  especially  reproduction.     Actinic 


MILITARY  RECONNAISSANCE  127 

printing  processes  are  often  too  slow  for  satisfactory  reproduction 
in  the  field.  If  blueprinting  is  employed  the  rate  of  reproduction 
may  be  greatly  increased  by  using  brown  print  (maduro)  nega- 
tives, from  each  of  which  blueprints  may  be  produced  as  rapidly 
as  from  the  original  tracing.  The  hectograph  is  also  useful  for 
reproducing  small  sketches.  It  is  light,  portable  and  simple  in 
operation,  more  rapid  than  blueprinting,  and  has  a  further 
advantage  in  that  maps  in  several  colors  may  be  produced  in 
one  operation.  The  best  field  method  now  generally  employed 
is  lithography,  or  rather  zincography,  since  the  excessive  weight 
of  litho  stones  renders  them  inconvenient  for  rapid  transporta- 
tion. The  engineer  troops  are  accordingly  supplied  with  an 
efficient  and  portable  outfit  for  map  compilation  and  reproduc- 
tion, including  drafting,  photographic,  actinic  printing  and 
hthographic  (zinc)  apparatus.  This  is  one  of  the  most  important 
items  of  their  equipment. 

Fig.  67  indicates  the  manner  in  which  a  piece  of  ground  is 
contoured  l)y  the  methods  of  rapid  military  sketching  herein- 
before outlined.  For  the  sake  of  simplicity  such  features  as 
buildings,  fences,  trees,  etc.,  are  omitted,  although  these  would, 
of  course,  appear  on  a  complete  sketch  and,  moreover,  are 
important  as  references  and  control  in  plotting  the  critical 
points  of  the  terrain.  In  Fig.  A  the  sketcher  has  determined 
and  placed  upon  his  sheet  the  drainage  lines  of  the  area  with  a 
number  of  elevations  on  each.  He  has  also  determined  and 
plotted  the  horizontal  positions  and  elevations  of  the  tops  of 
hills  and  the  crests  of  ridges  and  of  the  points  where  there  is  a 
marked  change  in  slope,  as  at  830  in  the  northeast  portion  of 
the  area.  This  data  constitutes  the  control  or  skeleton  of  his 
sketch,  and  if  the  work  has  been  carefully  done  and  no  critical 
points  omitted  it  will  be  possible  to  make  a  fairly  accurate 
contoured  map  of  the  area  without  any  additional  information 
and  without  again  seeing  the  ground. 

It  was  observed  that  the  slopes  of  the  stream  beds  were  fairly 
uniform,  that  is  to  say,  in  this  case  there  were  no  waterfalls. 


128 


THE  ENGINEER  IN  WAR 


y 

1 

1 

861 

-860 

790/ 

873 

\ 
\ 

872« 

870 

I 
\ 

830         ^, 

\ 

\ 
\ 

\ 

1 
J* 

8i0             ■ 

■ ^ 

8S0                /I  1 

/ 

1 

1 

1 
1 
I 
1 

870 

I              >880 

/     1 
1      1 
/ 

/ 

/ 
/ 
/ 
/ 
/ 

88S 

/ 

/ 
/ 
/ 

/ 

/              * 

92 

8C5 

^^845 

Arrow  bead*  show  direction  of  water  flow. 


i 

k 

-867 

-8S0 

790/ 

r 

t 

J 

/ 

V 

873 

T  ^ 
^'«. 

'/ 

-^      \ 

872" 

870 

i 

y 

■*830      \ 

V       ^^ 

^ — ^ 

t 

-< 

-»86o            ;i 

lEf"""""""* 

y 

■^ 

♦«,« 

/  4 

/ 

\ 

850 

/ 

/ 

•910     1 

1 

/ 

f 

T 

/ 

1 

1 

* 

)^ 

/ 

/ 

«88S 

i860 
1^^ 

y 

/ 

♦■ 

-892 

-;« 

5 

Arrowheads  (except  those  appearing  also  on  il)  are  points  where 
contours  cross  streams  or  dry  runs. 

Fig.  67a. — The  evolution  of  a  military  contoured  sketch. 


MILITARY  RECONNAISSANCE 


129 


Fig.  676. — The  evolution  of  a  military  contoured  sketch. 


130  THE  ENGINEER  IN  WAR 

In  Fig.  B  the  sketcher  has  placed  the  contour  points  on  the 
drainage  lines.  These  may  be  spaced  uniformly  or  the  stream 
beds  may  be  made  slightly  steeper  at  their  upper  ends,  as  will 
usually  be  the  case.  The  sketcher  also  places  the  contour 
points  on  the  axis  of  the  ridge  in  the  eastern  part  of  the  area. 
As  the  plotted  elevations  indicate  a  change  of  slope  from  quite 
steep  at  the  bottom  to  a  gentle  slope  higher  up,  the  coiitour 
points  are  spaced  accordingly.  He  now  sketches  in  the  contours, 
on  the  controlling  points  thus  determined,  Fig.  C.  By  similar 
procedure  the  balance  of  the  area  is  filled  in  and  Fig.  D  presents 
the  complete  sketch. 

In  practice  the  contours  would  usually  be  sketched  on  the 
ground  or  "in  sight  of  the  facts."  Thus,  in  placing  the  contours 
shown  in  Fig.  C,  the  sketcher  might  stand  at  860  where  he 
could  see  the  drainage  lines  on  all  sides.  By  thus  viewing  the 
terrain  the  sketcher  would  note  the  small  details  of  the  ground 
forms  and  portray  them  on  his  sketch.  Thus,  the  small  fold 
or  drainage  line  beginning  at  850  near  the  center  of  the  area 
could  be  sketched  in  quite  accurately  by  eye,  even  if  it  had  not 
previously  been  included  in  the  skeleton,  as  shown  in  Fig.  A. 
For  purposes  of  instruction,  however,  the  sketchers  are  required 
to  prepare  Fig.  A  in  the  field  and  then  to  fill  in  the  contours  with- 
out viewing  the  terrain.  This  gives  them  excellent  instruction 
in  portraying  ground  forms  and  by  comparing  their  sketches 
thus  prepared  with  a  more  accurate  map  of  the  same  area  thoy 
will  note  the  faults  they  have  committed,  and  especially  the 
critical  points  which  they  have  failed  to  perceive  and  locate  in 
the  field. 

MAP  READING 

While  not  every  officer  and  non-commissioned  officer  will  be 
called  upon  to  make  maps  and  sketches,  all,  from  the  highest  to 
the  lowest,  will  frequently  have  to  read  and  interpret  them.  An 
officer  who  is  not  an  adept  in  map  reading  will  be  at  a  great  dis- 
advantage in  the  exercise  of  independent  command.     The  map 


MILITARY  RECONNAISSANCE  131 

should  convey  to  his  mind  a  fairly  accurate  picture  of  the  actual 
ground,  and  he  should  be  able  to  rapidly  and  accurately  obtain 
any  information  which  the  map  can  furnish.  Such  facility  is 
acquired  only  by  long  practice.  To  locate  one's  position  on  a 
map,  to  orient  it,  to  determine  the  difference  of  elevation  or  the 
distance  between  two  points  are  apparently  simple  matters,  but 
if  it  is  a  question  of  moving  troops  there  are  many  other  con- 
siderations. What  are  the  widths,  character  and  condition  of 
the  roads?  What  grades  will  be  encountered?  At  what  aver- 
age speed  can  a  wagon  train  move?  Is  the  road  open  or  shady? 
Can  it  be  easily  observed  from  adjacent  heights,  or  possibly  fired 
upon?  What  towns  lie  upon  it?  Is  there  a  telegraph  line 
alongside?  Are  there  bridges  over  the  streams?  If  so,  are 
they  in  good  condition  and  amply  strong  to  carry  the  loads 
accompanying  the  army?  If  not,  how  long  will  it  take  the  en- 
gineers to  fix  them?  Are  there  fords  nearby?  What  are  the 
depths  of  water?  What  effect  do  floods  have?  Is  a  certain 
locality  suitable  as  a  camp  site  for  a  certain  body  of  troops? 
How  about  the  water  supply?  Is  there  shade?  Is  the  drain- 
age satisfactory?  Is  fuel  available?  How  should  the  various 
organizations  be  disposed?  Is  the  locality  defensible?  Where 
should  the  outpost  line  be  placed  and  how  many  men  will  be 
required  to  cover  it?  If  a  defensive  position  is  to  be  taken 
to  cover  some  important  point  or  some  movement  of  troops, 
where  is  the  best  general  line  for  occupation?  Can  the  enemy 
avoid  it  or  must  he  attack?  Is  there  natural  cover  available? 
How  about  the  roads  and  other  communications?  Are  there 
good  observing  stations  and  sites  for  the  artillery?  Is  the  field 
of  fire  satisfactory?  What  natural  obstacles  exist?  How  about 
the  facilities  for  retreat  or  withdrawal?  Are  the  flanks  secure? 
What  materials  for  construction  will  probably  be  available? 
Can  civilian  labor  be  secured — if  so — to  what  extent?  These 
and  many  similar  questions  must  be  tentatively  answered  from 
maps,  sketches  and  reports  of  reconnoitering  parties,  but  it  is 
to  be  remarked  that  the  final  dispositions  will  almost  invariably 


132  THE  ENGINEER  IN  WAR 

be  made  upon  the  ground  itself,  for  the  best  map  can  not  answer 
all  questions  that  arise. 

One  interesting  problem  that  is  often  encountered  in  military 
operations  is  that  of  visibility,  a  question  as  to  whether  a  certain 
point  or  area  is  visible  from  a  certain  other  point.  Such  a 
problem  can  seldom  be  solved  with  great  precision  on  a  map,  but 
an  approximate  solution  will  often  be  required.  Thus,  in  the 
case  of  a  movement  of  troops,  is  the  road  along  which  they  will 
march  visible  from  certain  commanding  points  in  the  vicinity? 
If  so,  what  parts  of  the  road?  If  it  is  desired  to  conceal  the  move- 
ment from  the  enemy,  as  will  usually  be  the  case,  such  observa- 
tion points  should  be  determined  and  either  avoided  or  occupied 
in  advance  in  order  to  prevent  the  enemy  from  doing  so.  Artil- 
lery requires  observing  stations  from  which  its  field  of  fire  can 
be  observed.  It  is  necessary  to  select  these  positions,  to  ascer- 
tain the  areas  visible  from  each,  to  determine  whether  obser- 
vation towers  are  needed  and,  if  so,  how  high  they  must  be,  etc. 

The  solution  of  visibility  problems  involves  the  construction 
of  profiles  (Fig.  68).  As  this  is  a  tedious  process  short  cuts  are 
usually  employed.  One  who  is  proficient  in  map  reading  can 
solve  the  less  critical  problems  at  a  glance.  If  there  be  inter- 
vening ridges  it  is  often  necessary  to  fix  the  height  of  the  line 
of  sight  at  such  ridges.  Visibility  problems  may  be  solved  by 
proportion  and  by  the  use  of  the  slide  rule.  The  following  rouph 
method  will  also  be  found  useful  in  many  cases.  A  red  rubber 
band  is  graduated  in  tens  and  hundreds  on  any  scale.  The  tens 
are  numbered,  the  hundreds  are  not.  Now  suppose,  for  example, 
that  the  elevation  of  the  point  of  sight  is  410  and  that  of  the  point 
to  be  observed  290.  Stretch  the  rubber  band  so  that  the  first 
90  falls  on  the  point  to  be  observed  and  the  second  10  following 
on  the  point  of  sight.  Then  the  elevation  of  the  line  of  sight 
where  it  crosses  the  intervening  ridge  is  read  on  the  band.  If 
this  is  greater  than  the  ground  elevation  as  shown  by  the  con- 
tours, the  two  points  are  mutually  visible,  each  from  each.  Of 
course  if  there  are  trees  growing  on  the  ridge  it  is  necessary  to 


MILITARY  RECONNAISSANCE 


133 


Fig.  68. — The  construction  of  a  profile. 


134 


THE  ENGINEER  IN  WAR 


MILITARY  RECONNAISSANCE  135 

make  allowance  for  these.  To  determine  what  area  is  visible 
from  a  given  point,  draw  a  number  of  radial  lines  from  the 
point.  An  inspection  of  the  map  will  usually  determine  the 
intervening  ridges  or  hills  which  will  limit  the  visibility.  Mark 
the  critical  points  on  each  line  of  sight.  Now  stretch  the  rubber 
band  so  that  the  proper  elevations  fall  on  the  point  of  sight  and 
an  intercepting  point,  look  along  the  band  and  find  the  point 
where  the  graduation  on  the  band  coincides  with  the  elevation 
on  the  map.  This  will  be  the  point  where  the  line  of  sight  strikes 
the  ground.  Look  back  along  the  band  and  make  certain  that  at 
all  points  between  the  point  of  sight  and  the  assumed  intercept- 
ing point  the  line  of  sight  is  above  the  ground.  By  joining  the 
points  thus  determined  with  broken  lines  the  approximate 
boundaries  of  the  visible  and  invisible  areas  are  determined. 
The  invisible  areas  should  be  shaded. 

Photography  is  of  little  practical  use  for  map  making  for 
military  purposes  except  in  the  case  of  photographs  taken  from 
a  balloon  or  aeroplane  at  a  considerable  height,  which  are  in 
effect  a  form  of  map.  But  photographs  are  a  valuable  accessory 
to  maps  in  giving  a  clearer  appreciation  of  the  terrain  as  it 
appears  to  the  eye.  They  are  of  great  value  for  showing  the 
construction  and  condition  of  bridges,  wharves,  buildings,  etc. 
Landscape  sketches  are  usually  of  more  value  than  photographs, 
inasmuch  as  they  give  special  prominence  to  the  important 
features  of  the  terrain,  omitting  the  mass  of  details  which  obscure 
the  critical  points  (Fig.  69). 

Acknowledgment. — Most  of  the  figures  accompanying  this 
chapter  are  taken  fro^l  ''MiUtary  Topography,"  by  Major 
C.  0.  Sherrill,  Corps  of  Engineers,  U.  S.  Army,  the  leading 
American  work  on  this  subject. 


CHAPTER  IX 
MILITARY  SANITATION 

A  sound  physique  and  rugged  health  are  essential  prerequisites 
of  military  training  and  military  service.  The  fighting  effi- 
ciency of  the  troops  is  directly  dependent  upon  the  maintenance 
of  their  health,  which  is  accordingly  of  prime  importance,  not 
only  from  a  humanitarian  but  more  particularly  from  a  purely 
tactical  point  of  view.  The  history  of  the  past  wars  shows  that 
the  losses  of  armies  due  to  sickness  have  far  exceeded  those  of 
battle.  Camp  epidemics  have  decided  the  issue  of  war,  the  fate 
of  nations  and  the  progress  of  civihzation.  Sanitation  may  be 
regarded  then  as  coordinate  with  strategy  and  tactics  in  the 
conduct  of  war. 

Sanitation  is  the  particular  field  of  the  medical  department 
but  its  success  in  this  field  is  contingent  upon  the  obedience  and 
intelligent  cooperation  of  all  officers  and  men  of  all  arms.  The 
sanitary  fimctions  of  the  engineers  are  distinctly  subordinate 
'to  those  of  the  medical  department,  arid  consist  in  executing 
the  more  important  engineering  operations  demanded  by  sani- 
tary requirements.  These  operations  are  similar  to  those  of 
the  civil  sanitary  engineer,  but  hke  other  works  of  miUtary  engi- 
neering, are  generally  less  formal  and  more  in  the  nature  of  make- 
shifts. Such  operations  will  be  required  wherever  troops  are 
assembled,  in  concentration  and  training  camps,  in  the  trenches 
and  on  the  march.        * 

On  the  battlefield,  in  the  presence  of  the  enemy,  efficient  sani- 
tation will  be  difficult  enough,  and  remarkable  are  the  make- 
shifts by  wliich  it  is  effected.  But  it  is  not  here  alone  that  sick- 
ness and  pestilence  will  exercise  their  baneful  influence.     The 

136 


MILITARY  SANITATION  137 

volunteer  army  must  be  mobilized  and  receive  its  final  training 
at  the  great  camps  that  will  be  estabUshed  for  that  purpose  in 
various  parts  of  the  country.  The  general  location  of  these 
camps  will  be  determined  by  strategical  considerations,  but  in 
the  selection  of  the  actual  sites  tactical  requirements  will  have  no 
weight  and  the  camps  should  be  located  with  a  view  to  efficient 
sanitation.  This  has  not  always  been  done.  The  raw  levies, 
uninstructed  in  outdoor  personal  hygiene  and  sanitation,  have 
often  been  assembled  in  great  numbers  in  unsanitary  localities 
and  sickness  and  camp  epidemics  have  been  the  logical  results. 
The  sites  for  these  concentration  camps  should  be  carefully 
selected  in  time  of  peace,  taking  into  consideration  the  strategical 
and  sanitary  requirements.  While  it  will  not  always  be  prac- 
ticable to  reserve  large  areas  exclusively  for  this  purpose,  and 
to  provide  in  advance  the  communications,  drainage,  water  sup- 
ply, etc,,  yet  plans  should  be  made  by  which  the  sites  can  be 
rendered  promptly  available  when  needed.  The  necessary 
sanitary  measures  should  then  be  planned  in  time  of  peace  and 
carried  out  before  the  arrival  of  the  troops.  Subsequent  to  the 
arrival  of  the  troops  their  instruction  in  personal  hygiene  and 
the  rudiments  of  miUtary  sanitation  will  be  not  less  important 
than  their  instruction  along  other  Hues. 

The  most  important  engineering  operations  in  connection  with 
sanitation  are  water  supply,  drainage  and  sewage  disposal. 
Other  vital  engineering  requirements  of  the  sanitarian,  such  as 
transportation,  the  construction  of  hospitals,  depots,  etc.,  are 
neither  distinctly  military  nor  distinctly  sanitary.  If  the  mili- 
tary engineer  is  to  render  inteUigent  aid  to  the  sanitarian  he 
must  be  well  versed  in  the  principles  and  methods  of  civil  sani- 
tation and  capable  of  adapting  these  to  mihtary  needs,  often 
under  trying  circumstances. 

At  any  site  which  troops  are  to  occupy  for  a  considerable  time 
efficient  sanitary  measures  will  be  necessary  for  the  preservation 
of  their  health  and  morale.  This  will  apply  as  well  tp  defensive 
positions  on  the  battlefield  as  to  camps  at  some  distance  from  the 


138  THE  ENGINEER  IN  WAR 

theater  of  actual  conflict.  A  site  naturally  healthy  should  be 
selected  for  occupation  whenever  conditions  permit.  The  sit« 
should  be  well  drained  and  open  to  sun  and  air.  High  ground 
with  a  sandy  or  gravelly  soil  or  good  firm  turf  is  to  be  preferred. 
In  warm  weather  an  open  wood  affords  protection  from, the  heat 
while  permitting  the  circulation  of  air.  In  cold  weather  a 
southern  exposure  with  a  hill  or  wood  to  give  protection  from 
the  prevailing  wind  is  desirable.  Strategical  and  tactical  con- 
siderations are  usually  paramount,  but  the  most  healthful  site 
which  these  considerations  permit  should  always  be  selected. 
In  the  selection  of  the  site  the  engineer  will  of  course  be  called 
in  consultation.  Above  all,  an  ample  supply  of  good  water 
must  be  available,  since  impure  water  is  the  most  effective  means 
of  transmission  of  some  of  the  most  usual  and  dangerous  of  camp 
epidemics,  including  typhoid  fever,  dysentery  and  cholera. 
Drainage  should  be  efficient,  and  measures  adopted  for  dis- 
posing of  sewage  and  kitchen  waste.  When  flies  and  mosquitoes 
are  plentiful  special  measures  may  be  taken  to  abate  such  nuisance 
and  danger  as  their  presence  entails.  The  most  important  duty 
of  the  mihtary  sanitarian  is  not  to  cure  sickness  but  to  prevent  it. 
For  the  permanent  concentration  camps  one  of  the  approved 
civil  methods  of  water  supply  ma}-  be  adopted.  If  the  camp  1)0 
near  a  large  city  having  a  good  water  supply  the  latter  may  he 
used,  at  least  for  drinking  and  cooking  purposes,  the  use  of 
water  by  the  civil  population  being  curtailed  if  necessary.  The 
amount  of  water  to  be  supplied  is  indicated  by  the  experience 
of  civil  communities.  Many  civil  uses  of  water  may,  however, 
be  greatly  limited  or  entirely  dispensed  with.  These  may 
include  such  items  as  flushing  the  streets,  elaborate  water-borne 
sewage  sj'stems,  etc.  As  military  discipline  permits  thorough 
regulation  of  the  use  of  water,  much  of  the  waste  characteristic 
of  civil  communities,  especially  where  the  supply  is  unmeteretl, 
may  be  ehminated.  The  camp  may  also  to  some  extent  be 
located  and  arranged  with  a  view  to  facihtating  the  water 
supply.     It  will  usually  be  impracticable  to  adopt  the  modern 


MILITARY  SANITATION  139 

method  of  slow  sand  filtration  on  a  large  scale,  unless  such  has 
been  installed  during  peace,  since  the  construction  of  the 
filters  requires  considerable  time.  For  similar  reasons  a  gravity 
supply  is  to  be  preferred  to  one  which  requires  pumping.  Never- 
theless, pumping  must  often  be  resorted  to,  and  it  is  to  be  re- 
marked that  the  high  pressure  required  for  distribution  over  a 
wide  area  and  for  fire  protection,  etc.,  will  seldom  be  necessary. 
A  natural  site  where  a  storage  reservoir  of  adequate  capacity 
may  be  created  by  a  hastily  constructed  earth  dam  should  be 
sought.  If  its  elevation  is  such  that  pumping  may  be  avoided 
so  much  the  better.  A  camp  site  near  a  large  river  or  a  lake 
is  often  advantageous,  but  in  such  case  an  intake  and  pumping 
plant  will  usually  be  necessary,  and  possibly  also  settling  basins 
and  tanks  or  distributing  reservoirs.  Smaller  streams  may 
be  dammed,  always  upstream  from  the  camp.  The  storage 
reservoirs  may  serve  also  as  settling  basins  for  plain  sedimenta- 
tion and  chemical  coagulants  and  mechanical  filters  may  be 
used.  Deep-driven  wells  are  often  a  convenient  and  satisfactory 
source  of  supply.  Distillation  furnishes  the  purest  possible 
water,  but  is  usually  impracticable  on  a  large  scale.  It  may 
often  be  advantageously  emploj-ed  to  furnish  drinking  water 
for  small  commands.  The  most  common  method  of  providing 
potable  water  for  military  uses  is  by  boiling,  preceded  by 
sedimentation  where  necessary.  Boiling  for  five  minutes  will 
destroy  the  germs  of  typhoid  or  enteric  fever  and  of  cholera. 
Boiling  for  fifteen  minutes  will  destroy  all  pathogenic  germs. 
Stationary  and  portable  boilers  are  employed.  The  method 
has  the  disadvantage  that  it  requires  fuel  and  is  slow.  For 
these  reasons  many  experiments  have  been  made  to  devise  a 
form  of  mechanical  filter  suitable  for  military  uses.  No  en- 
tirely satisfactory  device  has  ever  been  produced.  In  their 
operations  on  the  western  battle  front  in  Europe  the  French, 
after  having  experimented  with  many  types  of  filters,  all  of  which 
were  unsatisfactory,  have  adopted  purification  by  the  use  of 
sodium  hypochlorite.     The  purified  water  is  distributed  to  the 


140  THE  ENGINEER  IN  WAR 

troops  in  wheeled  tanks,  and  this  method  is  said  to  be  satis- 
factory. While  it  would  often  be  practicable  to  pipe  the  supply 
of  drinking  water,  the  waste  would  probably  be  much  greater 
than  where  it  is  delivered  in  tanks.  Water  for  bathing  purposes, 
as  it  need  not  be  purified  and  often  not  even  clarified,  may  be 
advantageously  distributed  by  piping.  Wooden  stave  tanks 
and  gas  engine  pumping  plants,  as  they  are  easily  transported 
and  erected,  are  well  adapted  to  mihtary  uses. 

On  the  march  and  in  temporary  camps  some  dry  sewage 
method  must  usually  be  adopted.  The  simplest  scheme  of  this 
kind  is  a  pit  or  trench,  preferably  one  enclosed  or  sheltered  by 
a  screen  and,  if  necessary,  provided  with  a  cover  such  as  a 
tent  or  a  thatch  on  poles.  Earth  and  lime  are  employed  for 
covering  and  deodorizing  and  if  flies  are  abundant  the  pit  may 
be  screened.  Such  pits  with  their  shelters  are  known  as  latrines. 
When  a  camp  is  occupied  for  any  considerable  length  of  time  the 
latrine  method  is  objectionable.  A  more  sanitary  arrangement 
is  incineration.  There  are  many  forms  of  incinerators,  one 
especially  adapted  to  mihtary  uses  being  a  furnace  and  latrine 
combined,  the  whole  mounted  on  wheels  for  transport.  On  the 
battlefield  latrines  will  be  employed  in  the  trenches,  but  if  these 
are  to  be  occupied  for  some  time  the  pail  system  should  be 
employed,  the  contents  of  the  pails  being  removed  for  incinera- 
tion back  of  the  Une.  Another  expedient  would  be  water  closets 
and  cesspools,  but  as  the  latter  are  now  almost  universally 
condemned  septic  tanks  will  be  preferable  and  often  not  much 
more  difficult  to  provide.  Incineration  is  the  most  sanitary 
method  of  disposing  of  kitchen  waste. 

In  concentration  camps  more  elaborate  measures  are  prac- 
ticable which,  as  in  the  case  of  water  supply,  may  sometimes  bo 
carried  out,  or  at  least  planned  in  advance  of  the  outbreak  of 
hostihties.  These  may  include  the  most  approved  modern 
methods  of  sewage  disposal. 

Military  sanitation  bears  the  same  relation  to  civil  sanita- 
tion that  other  Unes  of  mihtary  engineering  bear  to  the  corre- 


MILITARY  SANITATION  141 

spending  lines  of  civil  work.  That  is  to  say,  it  is'  a  more  or  less 
hasty  and  makeshift  adaptation  of  civil  methods  to  miUtary 
needs.  To  achieve  success  under  the  difficulties  which  will  be 
encountered  in  war  time  the  mihtary  engineer  should  be  ac- 
quainted with  the  theory  and  practice  of  civil  sanitary  engineer- 
ing and  capable  of  adapting  them  to  military  needs. 


CHAPTER  X 
THE  MOBILIZATION  OF  MATERIAL  RESOURCES 

The  modern  theory  of  war,  as  we  have  seen,  contemplates  in 
it«  highest  development  not  only  the  universal  training  of  the 
personnel,  but  the  complete  mobilization  of  the  material  re- 
sources of  the  nation.  An  army  numbering  millions  requires 
in  its  operations  vast  quantities  of  supplies  of  all  kinds.  Unless 
these  supplies  are  forthcoming  as  needed  the  nation's  defenders, 
however  intelligently  organized  and  splendidly  trained,  will  be 
unable  to  successfully  oppose  the  fully  equipped  troops  they 
will  be  called  upon  to  meet  in  the  event  of  war  with  a  foreign 
power.  Such  has  been  the  situation  of  more  than  one  of  the 
nations  in  the  present  war. 

The  supplies  necessary  are  not  limited  to  weapons,  ammuni- 
tion, foodstuffs  and  clothing,  but  include  the  great  bulk  of  the 
products  of  our  farms,  mines,  forests  and  factories.  There  is 
also  demanded  the  service  of  our  transportation  systems  by  land 
and  water.  Our  material  resources  exceed  those  of  any  other 
nation  and  are  ample  for  the  prosecution  of  a  great  and  pro- 
tracted conflict.  They  are  at  present,  however,  very  poorly 
organized  from  the  point  of  view  of  military  necessity.  This  is 
plainly  indicated  by  the  lack  of  system,  the  delays  and  ex- 
travagance which  are  attending  the  furnishing  of  munitions 
of  war  to  the  European  nations.  Europe  has  paid  for  our 
inefficiency,  but  the  experience  acquired  by  our  manufacturers 
and  their  agents  will  be  of  undoubted  benefit  to  our  own  de- 
fensive polic}'. 

In  mobilizing  our  material  resources  it  is  necessary  first  to 
ascertain  our  probable  needs  in  the  event  of  war.  We  should 
then  investigate  and  make  record  of  the  sources  from  which 

142 


THE  MOBILIZATION  OF  MATERIAL  RESOURCES        143 

these  needs  may  be  supplied,  and  finally  execute  all  possible 
preliminary  measures  necessary  to  stimulate  production.  The 
problem  is  a  vast  one,  second  in  importance  only  to  the  training 
of  personnel.  We  can  here  consider  but  a  few  of  its  most 
saHent  features  under  the  three  general  heads,  to  wit : 

(a)  Probable  needs. 

(6)  Investigation  of  sources  of  supply. 

(c)  Stimulative  measures. 

The  material  required  for  the  conduct  of  war  may  be  classified 
under  two  heads: 

1.  Commercial  materials,  tools  or  appliances,  that  is  to  say,  those  which 
are  manufactured  and  used  in  large  quantities  in  times  of  peace:  and 

2.  Materials  or  equipment  which  are  peculiar  to  warfare  and  not  ordi- 
narily manufactured  at  all,  or  to  a  limited  extent  only,  for  commercial  pur- 
posesj'and  which  can  not,  therefore,  be  readily  obtained  on  short  notice. 

The  line  of  demarcation  between  the  two  classes  is  not  defi- 
nitely fixed.  Examples  of  the  first  class  would  be  axes,  barbed 
wire,  automobiles,  shoes,  anesthetics,  dynamite;  of  the  second 
class,  military  rifles,  portable  intrenching  tools,  haversacks, 
ponton  boats. 

In  the  event  of  war  the  regular  and  volunteer  forces  would 
be  called  at  once  to  the  colors  and  sent  to  the  front  as  rapidly  as 
they  could  be  equipped  and  trained  (in  the  case  of  volunteers). 
In  order  that  these  troops  may  be  promptly  equipped  for  duty 
it  will  be  necessary  to  keep  on  hand  in  time  of  peace  a  reserve  of 
material,  especially  of  the  second  class.  This  reserve  should 
obviously  be  no  larger  than  necessary — it  will  be  great  enough 
in  any  case.  Its  storage  and  care  will  be  expensive,  some  of  it 
will  become  obsolete  from  time  to  time,  and  some  will  deteriorate 
and  become  useless  in  storage — all  of  it  will  represent  an  invest- 
ment paying  no  direct  return  except  in  case  of  war.  The  amount 
of  each  item  of  this  reserve  will  depend,  first,  on  the  requirements 
of  war  and,  second,  on  the  predetermined  rate  of  production  and 
delivery  subsequent  to  the.  outbreak  of  war. 

The  plans  of  the  general  staff  will  contemplate  certain  con- 


144  TffE  ENGINEER  IN  WAR 

tingencies,  and  the  enrollment,  training  and  equipment  of 
successive  levnes  of  men  to  meet  these  contingencies.  Measures 
for  the  mobilization  of  the  material  resources  should  be  based 
upon  the  greatest  probable  requirements,  but  should  look  further 
to  the  possible  ultimate  utilization  of  all  our  resources.  A 
consideration  of  these  probable  requirements  will  indicate  what 
will  be  needed  at  the  outbreak  of  war  and  the  rate  of  production 
that  must  be  maintained  thereafter,  if  mihtary  operations  are 
not  to  be  delayed  or  hampered  by  lack  of  equipment  and  supplies. 
Supphes  for  military  purposes  can  be  more  readily,  quickly  and 
cheaply  obtained  the  more  nearly  they  conform  to  commercial 
tjrpes  and  standards.  Hence,  as  far  as  practicable,  they  should 
be  identical  with  or  similar  to  the  products  of  peace  time.  Many 
of  them,  of  course,  must  be  specially  adapted  to  military  needs. 
Having  tabulated  these  materials  the  next  step  is  an  investi- 
gation of  the  sources  of  supply.  Or,  to  avoid  delay,  the  t^^o 
investigations  may  be  prosecuted  simultaneously.  All  existing 
supplies  which  can  be  commandeered  in  case  of  need  without 
undue  hardship  to  the  civil  population,  such  as  automobiles  and 
animals,  should  be  located  and  recorded.  Every  manufactory 
in  the  land,  both  large  and  small,  should  then  be  investigated 
to  ascertain  what  material  it  could  produce  for  military  purpos(\s 
under  war  conditions.  The  somewhat  modified  requirements 
of  the  civil  population  during  the  war  must,  of  course,  also  ho 
considered  and  provided  for.  This  material  would  not  in  all 
cases  be  limited  to  the  regular  output  of  the  factory.  We  should 
consider  not  only  what  the  factory  does  ordinarily  produce  Init 
what  it  might  reasonably  be  counted  upon  to  produce  with  due 
regard  to  efficiency  and  economy.  It  will  be  necessary  also 
to  ascertain  the  time  that  would  be  required  to  equip  the  plant 
and  train  the  operatives  to  produce  a  different  line  of  products. 
The  average  American  industrial  plant  can  not  change  in  a 
day,  a  week,  or  even  a  month  from  its  regular  output  to  a  now 
line,  unless  careful  and  inteUigent .  preparation  be  made  in 
advance.     Without  such  preparedness  it  might  be  a  year  before 


THE  MOBILIZATION  OF  MATERIAL  RESOURCES        145 

the  plant  would  be  operating  in  an  efficient  and  economical 
manner  in  the  production  of  munitions,  and  then  perhaps  it 
might  be  too  late.  This  consideration  is  regarded  as  of  vital 
importance  to  the  national  defense. 

One  of  the  most  important  features,  therefore,  of  the  mobiliza- 
tion of  resources  is  a  study  of  the  stimulative  measures  that  may 
be  planned  in  advance  to  increase  the  rate  of  output.  There 
will  be  many  such  measures  and  they  must  be  carefully  thought 
out.  The  writer  undertakes  to  direct  attention  to  but  a  few  of 
these.  To  begin,  as  has  been  pointed  out,  military  supplies 
should,  as  far  as  practicable,  conform  to  established  standards. 
The  plans  and  specifications  of  these  materials  should  be  sub- 
mitted to  the  scrutiny  of  manufacturers.  They  will  thus  be 
able  to  point  out  many  modifications  which  will  cheapen  and 
speed  up  the  output  without  seriously  affecting  the  mihtary 
value  of  the  product.  So  far  as  possible,  the  manufacturers 
should  specialize  along  their  regular  lines.  The  revised  plans 
and  specifications  should  be  placed  with  the  manufacturers  for 
study  as  to  measures  necessary  for  rapid  production. 

Experimental  samples  of  each  class  of  supplies  should  be  pro- 
duced. This  would  indicate  the  methods  to  be  followed  in  manu- 
facture and  the  tools  and  machines  that  would  be  required  in 
addition  to  the  regular  equipment  of  the  factory.  These  models 
and  samples,  with  detailed  instructions  as  to  methods  of  fabrica- 
tion, should  then  be  placed  with  important  factories  or  groups 
of  factories.  All  special  tools,  machines,  gauges  and  patterns 
that  would  be  needed  should  be  devised.  An  ample  reserve  of 
these  accessories  should  be  kept  on  hand  by  the  government 
and  also  placed  in  the  factories  themselves,  and  necessary  ar- 
rangements made  to  augment  the  supply,  to  the  end  that  at  the 
outbreak  of  war  all  factories  from  which  material  would  be 
demanded  might  be  properly  and  quickly  equipped  to  produce 
this  material. 

The  assistance  of  the  manufacturers  themselves  will  be  most 
helpful.     Organizations  of  manufacturers  to  assist  in  the  investi- 

10 


146  THE  ENGINEER  IN  WAR 

gation  and  lining  out  of  plans  have  been  suggested.  A  thought- 
ful and  interesting  study  along  these  lines  was  presented  in  a 
pamphlet  recently  published  by  Mr.  Martin  J.  Gillen,  President 
of  the  Mitchell  Wagon  Co. 

It  should  be  remembered  that  many  of  our  most  important 
manufactories  lie  close  to  the  Atlantic  Seaboard  and  might  be 
subject  to  capture  in  case  of  invasion.  Due  allowance  should 
be  made  for  this  fact,  unfortunate  from  a  mihtary  point  of  view, 
and  corresponding  rehance  placed  upon  manufactories  farther 
in  the  interior  of  the  country  which  might  better  hope  to  enjoy 
immunity  from  hostile  interference. 

Having  determined  the  probable  rate  of  output,  a  reasonable 
allowance  should  be  made  for  a  possible  increase  in  demand  and 
for  the  possible  effect  of  the  emergencies  of  war  time  on  the 
predetermined  rate  of  output  of  industrial  plants. 

The  mobilization  of  our  industrial  personnel  would  be  a 
necessarj'  and  important  feature  of  this  general  scheme.  During 
the  war,  the  demands  of  the  civil  population  would  be  greatly 
modified  and  production  along  certain  Hnes  would  be  much 
diminished.  Certain  factories,  very  many  in  the  aggregate, 
could  be  devoted  exclusively  to  the  production  of  munitions  of 
war,  and  should  make  preparation  in  advance,  so  far  as  prac- 
ticable, to  take  up  this  work.  A  readjustment  of  the  industrial 
personnel  would  be  required  to  meet  war  conditions.  Many 
workmen  would  be  thrown  out  of  employment  by  diminished 
demand  for  certain  commodities  and  would  be  available  for 
transfer  elsewhere.  Many  also  would  be  drawn  for  service  in 
the  volunteer  army.  There  are  certain  industrial  operations  in 
which  women  are  nearly  if  not  quite  as  efficient  as  men.  The 
field  of  their  usefulness  should  be  investigated  with  a  view  to  re- 
leasing many  men  from  industry  to  serve  with  the  army.  In 
this  manner  the  women  could  perform  a  duty  quite  as  necessary 
and  important  as  actual  service  in  the  field. 

The  question  of  resources  is  not  limited  to  the  supply  of  muni- 
tions of  war.     The  government  must  look  also  to  the  needs  of 


THE  MOBILIZATION  OF  MATERIAL  RESOURCES       147 

the  civil  population  during  war  time.  For  a  nation  which  has 
not  been  self-sustaining  during  peace  (and  none  of  the  civiHzed 
nations  is  entirely  so)  and  finds  its  outside  sources  of  supply  cut 
off  by  war,  the  problem  may  be  a  serious  one.  The  United 
States  can  be  entirely  self-supporting.  We  can  produce  within 
our  own  borders  all  of  the  necessaries  of  life  and  all  the  munitions 
of  war,  and  this  is  an  important  element  in  our  potential  strength. 
Nevertheless  the  transition  from  the  conditions  of  peace  to  those 
of  war  will  be  a  tremendous  wrench  and  the  suffering  amongst 
certain  elements  of  our  population,  even  in  localities  not  directly 
touched  by  war,  will  be  great.  Many  of  the  industries  which 
supply  the  things  that  make  life  worth  living  without  being  abso- 
lutely necessary  to  its  mere  maintenance,  or  those  producing  for 
export  or  relying  on  imports  would  be  paralyzed  by  the  cessation 
of  demand  for  their  products  or  the  impossibility  of  marketing 
their  wares  or  obtaining  their  materials.  Their  employees 
would  be  thrown  out  of  work  and  would  have  to  be  otherwise 
provided  for.  Thus  the  demand  for  amusements,  such  as  the 
theater  and  music,  would  be  greatly  diminished,  as  also  the  de- 
mand for  luxuries  in  food  and  dress;  financial  operations,  trading 
in  stocks  and  bonds  and  real  estate,  building  operations,  the 
promotion  of  new  industries  would  all  be  greatly  curtailed;  im- 
port^ and  exports  might  be  absolutely  shut  off — our  foreign 
purchasing  and  selling  markets  closed  to  us  at  the  very  time  when 
the  home  markets  were  dull.  While  many  of  the  activities  would 
eventually  revive,  the  hardships  for  a  time  would  be  very  great. 
Governmental  aid  and  governmental  foresight  will  be  necessary 
to  maintain  confidence,  prevent  the  sudden  changes  in  condi- 
t  ions,  allay  panics,  and  afford  succor;  all  with  a  view  to  ameliorat- 
ing as  much  as  possible  the  hardships  which  war  inevitably 
entails.  As  the  government  depends  on  the  people,  so  also  would 
the  people  depend  on  the  government. 

To  conduct  the  investigations  and  institute  the  measures 
herein  outhned,  the  assistance  of  the  engineering  profession 
will  be  absolutely  necessary.     Steps  have  already  been  taken 


148  THE  ENGINEER  IN  WAR 

by  the  President  of  the  United  States  to  enlist  the  aid  of  the 
great  engineering  societies  in  carrying  out  these  investigations. 
As  the  inquiry  proceeds  the  stimulative  measures  which  may  be 
advantageously  employed  should  become  apparent. 

Many  manufacturers  and  engineers  with  manufacturing  ex- 
perience may  render  valuable  service  as  consulting  experts  to 
the  plants  engaged  in  the  production  of  war  munitions,  and  the 
engineering  profession  should  make  known  to  the  government 
the  identity  of  the  men  who  are  qualified  to  render  this  im- 
portant service.  In  the  event  of  war  there  would  be  organized 
in  the  War  Department  a  bureau  to  supervise  and  stimulate  the 
production  and  arrange  for  the  transportation  and  delivery  of 
supplies.     Many  engineers  would  be  employed  in  such  a  bureau. 

Manufacturers*  associations  and  labor  unions  must  play  their 
part  as  a  patriotic  duty.  It  is  very  desirable  that  we  be  spared 
the  humiliating  and  distressing  spectacle  of  frequent  strikes  over 
questions  of  wages  and  hours  of  labor  at  a  time  when  the  fate 
of  the  nation  is  in  the  balance. 

In  the  event  of  war  the  demands  on  our  transportation  systems 
will  be  very  heavy  and  it  is  necessary  that  we  take  careful  ac- 
count of  our  stock.  Many  railroads  and  steamship  lines  would 
be  taken  in  complete  charge  by  the  federal  authorities  and  all 
would  be  subject  to  a  degree  of  federal  military  control.  This 
control  must  be  sufficient  to  meet  miUtary  needs  but  can  best 
be  exercised  through  the  medium  of  our  big,  experienced  rail- 
road men.  If  any  attempt  is  made  to  replace  entirely  the 
expert  personnel  of  the  railroads  with  army  officers  having  little 
or  no  experience  in  railroad  administration  and  operation,  a 
paralysis  of  our  transportation  systems  would  be  the  logical 
result. 

This  mobilization  of  our  resources  in  material  and  transporta- 
tion must  probably  of  necessity  be  based  on  the  voluntary  service 
which  is  contemplated  by  our  military  policy.  Nevertheless, 
as  the  government  has  the  power  to  institute  compulsory  service 
in  case  of  need,  so  also  has  it  the  power  to  commandeer  the 


THE  MOBILIZATION  OF  MATERIAL  RESOURCES        149 

output  of  our  factories,  and  even  to  regulate  the  sale  of  the 
necessaries  of  life  to  the  civil  population. 

One  question  not  to  be  overlooked  is  that  of  the  prices  to  be 
paid  for  war  material.  The  prices  charged  the  European  nations 
by  American  manufacturers  have,  in  general,  been  excessively- 
high,  due  in  large  measure  to  our  lack  of  knowledge  of  require- 
ments and  our  inefficiency  in  a  new  field  of  industry.  It  is  be- 
lieved that  our  manufacturers  generally  would  have  no  wish 
to  derive  excessive  and  unreasonable  profits  from  the  agony  of 
the  nation.  And  on  the  other  hand,  they  should  not  be  required 
to  bear  more  than  their  share  of  the  burden  by  being  paid  less 
than  the  cost  of  production.  It  is  in  the  interest  of  both  parties 
that  fair  and  reasonable  prices  should  be  fixed  upon  in  conference 
and  revised  from  time  to  time  to  meet  changed  conditions.  The 
prices  should  not  be  perfectly  rigid  but  capable  of  adjustment, 
perhaps  on  a  "cost  plus  fair  profit '*  basis,  or  on  some  other 
basis  which  would  avoid  the  necessity  for  audit  of  the  manu- 
facturers' accounts. 

The  mobilization  plans  and  data  should  be  kept  up  to  date. 
The  opening  of  new  factories,  the  enlargement  or  discontinuance 
of  any  already  Usted  should  be  noted,  and  allowance  made  for 
the  effect  of  changes  in  •  industrial  conditions,  etc.  Plans  and 
specifications  should  be  modified  or  improved  where  necessary 
to  meet  changed  conditions  or  keep  pace  with  industrial  progress 
and  invention.  Schedules  of  prices  as  agreed  upon  or  fixed  by 
the  government  after  investigation  should  be  prepared,  and  the 
quota  of  each  factory  determined  and  assigned. 

With  this  information  as  to  our  resources  in  hand,  and  with 
all  practicable  stimulative  measures  in  effect  the  government 
will  be  able  to  avoid  much  of  the  delay  and  confusion  which  have 
in  the  past  so  frequently  marred  the  success  of  mihtary  operations. 
It  will  be  possible  to  intelligently  determine  the  nature  and 
amount  of  the  reserve  supplies  and  equipment  which  should 
be  kept  on  hand,  and  the  number,  capacity  and  location  of  the 
government  munition   plants  which   should   be  maintained  in 


150  THE  ENGINEER  IN  WAR 

time  of  peace.  In  common  with  the  training  of  our  personnel 
this  mobiUzation  of  our  resources  in  advance  of  the  outbreak 
of  war  will  cost  money — not  a  small  sum.  But  in  the  event  of 
war  the  returns  on  the  investment  would  be  large.  And  as  with 
most  things  that  are  worth  having  this  security  is  worth  paying 
for.  We  must  divorce  ourselves  completely  from  the  false  hope 
that  we  can  obtain  something  for  nothing — a  hope  be  it  said, 
long  dear  to  the  hearts  of  the  American  people,  and  which  has 
too  frequently  in  the  past  been  characteristic  of  our  military 
pohcy. 

In  conducting  the  investigations  as  to  resources  and  in  super- 
vising and  stimulating  the  output,  the  engineering  profession 
can  render  a  most  valuable  patriotic  service  as  intermediaries 
between  the  War  and  Navy  Departments  and  the  producers. 
The  country  will  be  greatly  dependent  upon  the  profession  in 
this  matter,  since  there  is  no  other  class  of  men,  civil  or  military, 
so  well  qualified  to  perform  this  important  duty. 

Because  of  our  vast  resources  we  have  a  tendency  to  regard 
the  question  of  supplying  the  sinews  of  war  rather  lightly.  We 
are  aware  that  the  resources  exist  and  we  comfort  ourselves  with 
the  hope  that  the  supply  of  suitable  manufactured  material  is  a 
matter  that  will  take  care  of  itself,  although  we  should  know  that 
such  is  not  the  fact  and  that  intelligent  preparation  in  advance 
is  just  as  necessary  as  in  the  matter  of  personnel.  The  nation 
whose  resources  in  material  are  limited  must  look  with  especial 
care  to  the  conservation  and  mobihzation  of  these  resources. 
Because  our  resources  are  not  limited  we  give  ourselves  little 
concern  in  the  matter.  But  are  we  not  short-sighted  in  this 
respect?  Are  we  not,  to  use  a  slang  expression,  ''overlooking 
our  best  bet?"  There  has  been  hardly  a  miUtary  campaign  in 
the  history  of  the  world  in  which  the  belligerents  have  not  been 
more  or  less  hampered  by  a  shortage  of  ammunition  and  supplies, 
either  immediate  or  prospective.  Thus  in  the  present  war, 
Russia  on  several  occasions  has  been  unable,  in  spite  of  ample 
personnel,  to  successfully  oppose  the  German  troops  because  of 


THE  MOBILIZATION  OF  MATERIAL  RESOURCES       151 

a  shortage  of  material,  and  she  has  been  compelled  to  forego 
success  which  might  have  been  gained,  and  has  been  forced  to 
sacrifice  many  valuable  lives  which  might  otherwise  have  been 
spared.  Several  of  the  great  ''drives"  indulged  in  by  various 
belligerents  have  fallen  far  short  of  a  full  measure  of  success 
partly  because  an  inexhaustible  supply  of  ammunition  was  not 
available. 

Now  it  is  true  that  we  possess  accumulated  wealth  and  material 
resources  exceeding  those  of  any  other  nation,  and  our  manufac- 
turing equipment  and  methods  are  the  greatest  and  most  efficient 
in  the  world.  If  our  advantages  in  these  respects  could  be 
brought  to  bear  we  could  furnish  the  materials  of  warfare  at  a 
rate  with  which  no  other  nation  could  keep  pace.  Should  we  not 
take  advantage  of  these  circumstances  to  insure  our  success  in 
case  of  war,  and  to  purchase  that  success  with  the  least  expendi- 
ture of  our  most  valuable  possession — the  lives  of  the  nation's 
defenders?  In  other  words,  if  a  fighting  man  knows  that  he  has 
an  inherent  advantage  over  all  possible  opponents  in  some  one 
particular  which  they  can  not  evade,  is  he  not  wise  if  he  develops 
this  advantage  to  the  utmost  and  then  conducts  the  combat  in 
such  a  manner  as  to  make  his  advantage  the  determining  factor 
in  the  result?  Superior  material  alone  can  not  win  battles  nor 
compensate  the  lack  of  trained  personnel.  But  its  possession 
constitutes  an  advantage  which,  other  things  being  equal,  will 
determine  the  issue  of  the  conflict. 

Sir  John  French,  late  commander-in-chief  of  the  British  forces 


"The  power  of  defense  conferred  by  modern  weapons  is  the  main 
cause  for  the  long  duration  of  the  battles  of  the  present  day,  and  it  is 
this  fact  which  mainly  accounts  for  such  loss  and  waste  of  life.  Both  one 
and  the  other  can,  however,  be  shortened  and  lessened  if  attacks  can  be 
supported  by  a  most  efficient  and  powerful  force  of  artillery  available; 
but  an  almost  unlimited  supply  of  ammunition  is  necessary,  and  a  most 
liberal  discretionary  power  as  to  its  use  must  be  given  to  artillery  com- 
manders. I  am  confident  this  is  the  only  means  by  which  great  results 
can  be  obtained  with  a  minmuim  of  loss." 


CHAPTER  XI 

HOW  MAY  THE  ENGINEERS   AND   CONTRACTORS   OF 

AMERICA  PREPARE  TO   MEET  THE  MILITARY 

OBLIGATIONS    OF    CITIZENSHIP? 

We  have  now  considered  our  present  military  policy  and  have 
seen  how  this  policy  precludes  that  thorough  preparation  for 
war  which  is  possible  only  by  means  of  large  standing  armies 
and  trained  reserves.  It  will  be  apparent  to  the  reader  that 
the  national  defense  reUes  at  present  chiefly  upon  the  patriotic 
willingness  of  our  citizens  to  partially  prepare  themselves  during 
peace  for  volunteer  duty  in  war.  We  have  briefly  reviewed  some 
of  the  principal  operations  of  military  field  engineering  and  have 
indicated  the  essential  differences  between  miUtary  and  civil 
practice. 

In  what  respects  are  our  civil  engineers  and  contractors  quali- 
fied to  meet  the  military  obligations  of  citizenship,  and  what  may 
they  do  under  present  conditions  to  increase  their  efficiency? 

There  is  no  class  of  our  citizens  more  intelligent  or  more 
patriotic  than  the  engineering  profession.  But  patriotism  which 
finds  its  expression  in  tear-dimmed  eyes  and  choked  throats  is 
of  no  practical  value  to  the  national  defense.  The  highest  form 
of  patriotism,  the  only  useful  form,  is  that  which  recognizes  the 
obligation  of  citizenship  and  voluntarily  prepares  to  meet  it. 

The  engineer  oflicer,  as  we  have  seen,  must  be  both  a  soldier 
and  an  engineer.  If  it  be  necessary  for  the  volunteer  candidate 
to  acquire  both  these  qualifications,  a  considerable  period  will 
be  required  for  his  proper  training  and  he  will  not  be  ready  to 
take  the  field  at  the  same  time  as  the  volunteers  of  other  arms. 
Our  civil  engineers  and  contractors,  possessing  in  advance  the 
technical  training  in  construction,  constitute  the  best  material 

152 


MILITARY  OBLIGATIONS  OF  CITIZENSHIP  153 

for  the  supply  of  engineer  officers.  Contractors  may  be  of  very 
great  help.  The  hustling  American  contractor  possesses  most 
of  the  qualifications  so  necessary  in  the  successful  military 
engineer.  He  is  often  in  these  days  a  man  with  technical  training, 
he  is  always  used  to  outdoor  work,  he  knows  how  to  handle  men 
and  is  familiar  with  construction  plant,  he  has  initiative  and 
resource  (otherwise  he  would  seek  a  different  profession),  and  he 
appreciates  the  importance  of  speed  in  construction  work.  The 
eye  of  the  military  appraiser  turns  appreciatively  upon  the 
contractor,  who  possesses  so  many  of  the  qualifications  he  seeks. 
Contractors*  foremen,  being  used  to  handUng  men  and  outdoor 
construction,  will  constitute  excellent  material  for  non-com- 
missioned officers  of  engineers — the  pioneers  of  the  mobile  army. 
For  the  rank  and  file  of  the  volunteer  engineer  battalion  we  may 
find  ample  material  in  our  great  industrial  organization.  Of  all 
these  candidates  there  is  none  more  valuable  than  the  man  who 
has  had  experience  as  a  laborer  on  general  contract  work.  He  is 
usually  handy,  used  to  outdoor  work  and  exposure  and,  to  a  con- 
siderable degree,  is  disciplined  in  a  miUtary  sense.  The  con- 
tractor, his  foreman  and  his  gang  are  of  great  value  as  a  military 
asset.  Men  with  some  outdoor  experience  will  ordinarily  be 
preferable  to  those  whose  careers  have  been  limited  to  the 
office. 

But  however  thorough  his  technical  training,  however  ex- 
tensive his  experience,  and  however  great  his  natural  adaptability 
and  resource,  the  civihan  engineer  has  very  much  indeed  to  learn 
before  he  will  be  qualified  to  perform  his  military  duties.  He 
must  learn  his  duties  as  a  soldier,  acquire  a  practical  knowledge 
of  tactics,  and  adapt  his  civil  engineering  knowledge  to  military 
requirements.  In  most  instances  he  must  divest  himself  of 
certain  preconceived  ideas  and  methods.  In  view  of  the  very 
short  time  that  will  be  allowed  for  intensive  training  after  the 
outbreak  of  war  before  the  volunteer  army  will  be  called  upon 
to  take  its  place  in  the  line  of  battle,  it  is  absolutely  essential 
that  some  portion  of  this  necessary  training  be  obtained  in  time 


154  THE  ENGINEER  IN  WAR 

of  peace,  especially  in  the  case  of  engineers.  How  may  this  be 
accomplished?  Assuming  the  patriotic  willingness  of  the  en- 
gineering profession  to  meet  the  obligations  of  citizenship,  how 
may  they  be  afforded  the  opportunity  to  acquire  training? 

The  first  step  manifestly  is  to  interest  the  profession  in  this 
important  matter  of  national  defense.  They  must  be  brought 
to  a  realization  of  what  our  military  policy  is,  the  extent  of  its 
reliance  upon  voluntary  service,  and  how  important  is  the  part 
of  the  engineer  in  any  scheme  of  defense  that  is  likely  to  be 
adopted  by  the  American  people.  It  is  not  only  necessary  to 
arouse  this  interest  on  the  part  of  the  profession  but  to  maintain 
it,  which  is  equally  important  and  far  more  difficult.  With  a 
great  war  now  going  on  in  Europe  there  is  little  difficulty  in 
interesting  the  people  of  this  country  in  miUtary  affairs.  But 
experience  shows  that  our  martial  ardor  cools  very  rapidly  as 
the  scenes  of  actual  warfare  recede  into  the  past. 

It  will  be  necessary  to  devise  some  system  by  which  those  men 
who  are  willing  to  undergo  training  can  be  instructed  in  the 
duties  of  military  engineering.  It  is  too  much  to  expect  of  the 
average  civilian  engineer  that  he  would  pursue  a  lonely  course  of 
study  on  a  subject  outside  of  his  regular  practice,  one,  moreover, 
which  holds  out  no  promise  of  financial  return.  The  driving 
force  or  incentive  to  the  pursuit  of  such  study  would  be  lacking, 
and  the  men  would  be  glad  to  have  some  form  of  compulsion  or 
obligation  applied.  Moreover,  such  study  would  produce  little 
result  except  under  the  guidance  of  professional  engineer  officers. 
Also,  the  study  should  be  supplemented  by  practical  training 
in  the  field.  To  produce  results  then,  it  is  apparent  that  this 
instruction  must  be  subsidized  and  directed  by  the  War  Depart- 
ment. The  engineering  societies  might  advantageously  act  as 
intermediaries  between  the  government  and  the  individuals, 
chiefly  in  the  important  matter  of  attendance,  though  it  is  not 
intended  to  suggest  that  the  instruction  be  limited  to  members  of 
such  societies. 

Several  schemes  for  such  instruction  suggest  themselves.     A 


MILITARY  OBLIGATIONS  OF  CITIZENSHIP  155 

number  of  colleges  and  universities  have,  at  present,  courses  of 
military  instruction,  and  it  is  possible  that  the  number  of  such 
will  be  increased  in  the  not  distant  future.  At  engineering 
colleges  this  military  instruction  might  readily  be  extended  to 
include  a  course  in  practical  miUtary  engineering,  with  class-room 
work,  lectures  and  field  instruction.  The  course  would  cover 
the  more  important  duties  that  have  been  heretofore  outlined. 
This  course  would  be  similar  to  that  now  pursued  at  the  U.  S. 
Military  Academy,  the  Federal  government  cooperating  with 
the  institution  in  furnishing  instructors  and  equipment.  Such  a 
course  would  have  considerable  military  value  and  would  cer- 
tainly be  useful  also  from  a  purely  civil  point  of  view.  It  could 
be  readily  inaugurated  and  the  expense  would  be  inconsiderable 
in  comparison  with  the  benefits.  Schools  having  such  depart- 
ments could  afford  some  of  the  tactical  and  technical  training 
which  the  profession  of  military  engineering  demands. 

rhe  problem  of  effectively  reaching  the  graduates  or  practicing 
engineers  is  more  difficult.  It  might  be  accomplished  by  an 
application  of  the  "business  men's  camp"  experiment,  such  as 
was  conducted  recently  at  Plattsburg,  N.  Y.,  and  at  other  places. 
The  greatest  difficulty  in  the  way  of  success  is  that  of  attendance. 
This,  of  course,  nmst  be  entirely  voluntary,  and  is  in  the  hands 
of  the  engineers  themselves  and  of  their  employers.  It  is  prob- 
able that  many  patriotic  employers,  if  they  could  be  made  to 
realize  the  great  need  for  and  importance  of  such  training,  would 
pledge  themselves  to  grant  leave  with  pay  to  engineers  desiring 
to  attend  the  instruction.  It  is  unfortunately  true  that  under 
our  present  military  policy  we  must  appeal  to  and  rely  largely 
for  success  on  the  patriotic  spirit  of  individual  citizens.  The 
burden  is  thus  unequally  distributed  and  must  always  be  unless 
compulsory  service  is  adopted.  The  federal,  state  and  municipal 
governments,  which  employ  large  numbers  of  civilian  engineers, 
might  well  set  a  good  example  in  this  way  by  making  it  possible 
for  their  technical  employees  to  attend  such  instruction  camps. 
If  systematic  attendance  can  be  secured  all  other  difficulties  in  the 


156  THE  ENGINEER  IN  WAR 

way  of  a  reasonable  measure  of  success  may  be  overcome.  To 
obtain  the  best  results,  Congressional  action  would  probably  be 
necessary.  There  would  be  many  details  to  work  out,  but  the 
scheme  holds  some  promise  of  success  and  is  at  least  worth  an 
experiment.  The  writer  is  aware  that  from  the  point  of  view  of 
efficiency  the  scheme  has  disadvantages  in  common  with  all  other 
schemes  based  on  voluntary  service.  But  we  must  face  condi- 
tions as  we  j&nd  them  and  do  the  best  we  can  under  the  difficulties 
that  exist.  Rational  preparedness  for  defense  is  necessary  for 
the  maintenance  of  peace  and  dignity — indeed  for  the  assurance 
of  our  continued  national  existence.  As  our  late  Secretary  of 
War  has  pointed  out,  if  we  wish  to  avoid  compulsory  service  on 
the  one  hand  and  almost  utter  defenselessness  on  the  other,  our 
citizens  must  prove  that  a  voluntary  system  based  on  patriotism 
can  be  relied  upon  to  insure  adequate  defense,  even  if  it  does  not 
provide  the  best  possible  defense. 

Field  training  in  military  engineering  has  been  developed  to  a 
high  degree  of  practical  efficiency  in  the  regular  army  and, 
under  the  supervision  of  officers  of  the  Corps  of  Engineers,  can 
be  readily  adapted  to  the  instruction  of  civilians.  The  govern- 
ment owns  or  may  obtain  the  use  of  tracts  of  land  suitable  for 
the  instruction  camps  in  the  vicinity  of  many  large  cities,  such 
as  New  York,  Chicago,  San  Francisco,  St.  Paul  and  MinneapoHs, 
Kansas  City,  Washington,  etc.  The  engineers  resident  in  such 
cities  could  thus  reach  the  camp  at  a  small  expense  in  time  and 
money.  Each  camp  would  be  in  charge  of  several  regular  engi- 
neer officers  with  a  detachment  of  engineer  troops  and  the 
necessary  equipment  in  the  way  of  instruments,  tools  and 
materials. 

The  course  of  instruction  should  be  prepared  in  advance  and 
should  be  varied  and  progressive  to  stimulate  interest  while 
carefully  avoiding  ennui  or  unnecessary  fatigue.  As  in  the  school 
training,  previously  referred  to,  it  should  be  along  both  tactical 
and  technical  lines.  The  details  of  camp  life  and  the  operations 
of  field  engineering  are  essentially  interesting  and  the  course  of 


MILITARY  OBLIGATIONS  OF  CITIZENSHIP  157 

instruction,  if  intelligently  carried  out,  would  leave  on  the 
students  the  impression  of  having  enjoyed  a  profitable  and 
pleasant  vacation,  and  this  would  go  far  toward  insuring  their 
attendance  at  subsequent  sessions.  More  advanced  courses 
would  be  prepared  for  men  in  attendance  at  their  second  or 
third  encampment.  The  instruction  should  properly  be  extended 
over  several  encampments.  It  would  include  camping  methods, 
camp  administration  and  sanitation,  simple  infantry  drill  and 
the  manual  or  arms,  marches,  security  measures  in  camp  and  on 
the  march,  battle  exercises,  target  practice,  and  instruction  in 
practical  military  engineering  along  the  lines  heretofore  dis- 
cussed. The  instruction  would  include  examinations  and 
discussions  of  previously  constructed  works,  demonstrations 
by  the  regular  detachment,  the  actual  construction  of  simple 
bridges,  sections  of  road,  trenches,  obstacles,  etc.,  the  use  of 
the  ponton  equipage,  demolition  and  sketching  by  the  students 
themselves,  the  solution  of  simple  tactical  problems,  including 
in  particular  the  selection  and  organization  of  a  defensive  posi- 
tion, the  writing  of  orders,  lectures,  critiques  and  discussions. 
A  very  simple  course  of  instruction  along  these  general  lines 
would  require  several  successive  encampments.  Such  a  course 
would  not  make  expert  military  engineers  of  the  students,  but 
it  would  afford*  them  a  practical  conception  of  military  methods, 
show  them  how  much  there  is  to  be  learned,  and  stimulate 
their  interest  in  military  affairs.  They  would  undoubtedly  be- 
come more  valuable  as  a  military  asset  than  perfectly  green 
men  having  no  conception  of  the  nature  of  military  operations. 
This  field  training  could  advantageously  be  supplemented 
by  a  correspondence  course  of  practical  problems  in  miUtary 
tactics,  map  reading,  and  mihtary  engineering,  accompanied 
by  a  course  of  reading.  Reading  alone  would  be  of  little  value, 
inasmuch  as  we  obtain  no  mental  training  when  another  does  our 
thinking  for  us,  and  even  the  knowledge  acquired  is  quickly 
forgotten.  It  is  experience  and  responsibility  that  develop 
judgment,  initiative  and  the  power  of  decision.     When  a  student 


158  THE  ENGINEER  IN  WAR 

reads  a  text-book  on  the  art  of  war  the  responsibility  for  the 
facts  alleged  and  the  deductions  made  rests  entirely  upon  the 
,  author.  From  such  works  the  student  temporarily  acquires  a 
.  certain  amount  of  information,  but  he  certainly  assumes  no 
mental  responsibility  and  without  this  he  receives  no  training. 
When,  however,  he  undertakes  the  independent  solution  of  a 
practical  problem,  whether  in  the  field  or  at  his  desk,  the  re- 
sponsibility rests  upon  his  shoulders  alone  and  the  results  he 
obtains  are  impressed  upon  his  mind  as  practical  experience. 
These  principles  should  form  the  basis  of  the  instruction  in  the 
field  work  and  correspondence  courses.  Reading  is  indeed  of 
value  but  has  its  greatest  value  in  connection  with  original  and 
independent  effort  on  the  part  of  the  student. 

The  solution  of  these  practical  military  problems,  whether  on 
a  map  or  in  the  field,  constitutes  what  is  known  as  the  applicatory 
method  of  military  instruction.  It  is  the  method  which  is  ptinsucd 
by  all  modern  armies,  being  properly  regarded  as  the  best  sub- 
stitute possible  in  time  of  peace  for  the  actual  experiences  of 
war.  Without  doubt  this  study  is  one  of  the  most  stimulating 
and  entertaining  of  mental  activities.  A  brief  survey  of  the 
method  will  therefore  be  of  interest.  The  problem  as  stated 
sets  forth  the  situation  of  or  circumstances  surrounding  a  certain 
imaginarj^  body  of  troops  of  which  the  student  is  assumed  to  be 
the  supreme  or  one  of  the  subordinate  commanders.  The 
statement  covers  the  position  and  strength  of  the  friendly 
troops,  the  local  conditions  as  to  terrain,  weather,  etc.,  certain 
information  concerning  the  enemy,  usuall}^  more  or  less  incomplete 
and  inexact,  the  orders  and  instructions  of  higher  authority,  etc. 
From  a  careful  consideration  of  all  this  information  the  com- 
mander shapes  his  course  of  action.  He  first  determines  his 
mission  or  purpose.  Often  this  will  be  embodied  in  the  orders 
he  has  received,  but  circumstances  may  arise  which  compel  him 
to  disregard  orders  which  did  not  contemplate  these  circum- 
stances. His  mission  must  then  be  deduced  from  his  knowledge 
of  the  situation  as  a  whole  and  of  the  wishes  or  intention  of  his 


MILITARY  OBLIGATIONS  OF  CITIZENSHIP  159 

superior.  It  may  demand  a  course  of  action  at  variance  with 
the  orders  he  has  received  and  it  is  here  that  his  judgment  is 
called  into  play.  Having  determined  his  mission,  the  com- 
mander reviews  the  various  courses  open  to  him  and  comes  to  a 
decision  on  the  course  which  appears  to  offer  the  greatest  promise 
of  success.  This  decision  will  require  a  rapid  but  thorough 
consideration  of  all  the  possibiUties  of  the  situation.  He  next 
prepares  the  details  of  a  plan  for  carrying  out  his  decision  and 
finally  embodies  this  plan  in  orders  to  his  subordinates.  The 
review  or  estimate  of  the  situation,  the  deduction  of  the  true 
mission,  the  arrival  at  a  decision,  and  the  preparation  of  the 
plan  and  orders  constitute  the  solution  of  the  problem.  These 
interesting  and  instructive  mental  processes  will  be  no  innovation 
in  the  brain  of  any  thinking  man,  inasmuch  as  they  are  char- 
acteristic, not  only  of  military  problems,  but  of  all  the  serious 
affairs  of  life. 

Individuals  who  had  received  training  of  this  nature  in  college, 
or  who  had  attended  a  certain  stipulated  number  of  instruction 
periods  in  camp,  or  both,  should  be  given  an  opportunity  to 
qualify  by  suitable  examination  for  a  commission  in  the  volunteer 
engineers.  Such  a  commission  might  properly  carry  with  it  a 
small  allowance  to  be  paid  by  the  federal  government.  The 
possibility  of  obtaining  such  a  commission  would  have  a  stimu- 
lating effect,  especially  amongst  the  younger  men  since,  even 
without  a  money  allowance,  it  would  constitute  an  honorable 
distinction.  The  man  who,  while  pursuing  a  civil  calling, 
still  recognizes  the  obligations  of  his  citizenship  and  endeavors, 
even  to  a  small  degree,  to  fit  himself  for  the  discharge  of  those 
obligations,  is  and  should  be  recognized  as  the  best  type  of  practi- 
cal patriot.  Such  men  are  the  real  patriots  on  whom  alone  we  can 
rely  with  any  degree  of  confidence  for  the  maintenance  of  the 
national  defense.  The  writer  believes  that  there  are  many  such 
men  amongst  our  engineers  and  contractors  and  that  the  nation 
would  do  well  to  afford  them  the  necessary  training,  which  they 
are  ready  to  receive  but  can  not  obtain  without  assistance. 


160  THE  ENGINEER  IN  WAR 

The  educational  schemes  which  have  been  outlined  are  to  be 
regarded  as  tentative  only.  Their  details  have  not  been  worked 
out  and  they  are  undoubtedly  incomplete  and  perhaps  faulty  in 
many  respects.  The  writer  does  not  urge  them  as  a  policy  to 
be  adopted.  Such  a  policy  must  be  based  on  careful  study  by 
our  governmental  and  military  authorities,  assisted  by  the  civil 
profession.  But  whatever  policy  may  be  adopted  for  the  mobili- 
zation of  our  resources  in  engineering  personnel  it  will  depend 
for  its  success  on  the  interest  and  volimtary  cooperation  of  the 
civil  engineers  of  America.  If,  actuated  by  a  spirit  of  practical 
patriotism,  our  engineers  desire  to  better  prepare  themselves  to 
meet  the  obligations  of  citizenship  in  the  defense  of  their  country, 
means  can  be  found  to  give  them  a  portion  of  the  training  of 
which  they  are  in  need. 


MILITARY  OBLIGATIONS  OF  CITIZENSHIP  161 


Field  signal  tower,  U.  S.  Army. 


BIBLIOGRAPHY 


WAR  DEPARTMENT 

OFFICE  OF  THE  CHIEF  OF  ENGINEERS 

Washington,  November  27,  1915 

Military  Reading  for  Civilian  Engineers 

By  authority  of  the  Secretary  of  War,  and  in  response  to 
frequent  requests,  the  following  suggested  list  of  reading  is  pub- 
lished for  the  information  of  civilian  engineers  desiring  to  inform 
themselves  on  mihtary  subjects: 

These  references  have  been  selected,  first,  with  a  view  to  giving 
to  engineers  unfamiliar  with  the  art  of  war,  a  general  survey  of 
that  subject — an  understanding  of  which  is  the  first  essential 
to  insure  successful  application  of  engineering  knowledge  and 
resources  to  military  purposes;  and,  second,  with  a  view  to  setting 
forth,  as  far  as  practicable,  the  ways  in  which  engineering  is 
applied  to  military  purposes  and  the  means  provided  therefor. 

Both  military  art  and  military  engineering  are  progressive,  and 
a  considerable  part  of  the  latest  and  most  detailed  information 
published  is  available  only  in  service  journals  of  our  own  and  for- 
eign armies.  This  is  particularly  true  of  technical  details  of 
seacoast  defense  (including  submarine  mining),  of  field  artillery, 
of  military  aviation,  and  the  influence  of  these  on  military  en- 
gineering. It  is  believed,  however,  that  the  fundamentals  of 
each  subject  are  well  covered  by  the  references  given  in  this 
list.  While  the  list  is  long,  the  relative  importance  of  the  various 
works  is  indicated,  and  suitable  comments  on  each  are  included, 
so  that  persons  using  the  lists  of  references  may  be  able  to  select 
those  which  particularly  interest  them. 

The  references  under  each  subject  are  generally  divided  into 
two  groups,  the  first  containing  the  more  essential  references,  and 

162 


BIBLIOGRAPHY  163 

the  second  those  suitable  for  persons  desiring  to  inquire  further 
into  the  subject. 

Note. — The  following  abbreviations  are  used: 
Supt.  of  Docs. — Superintendent  of  Documents,  Government  Printing  Office, 
Washington,  D.  C. 

Book  Dept. — Book  Department,  Army  Service  Schools,  Fort  Leaven- 
worth, Kans. 


"A»'  MILITARY  POLICY,  CONDUCT  OF  WAR,  AND  MILITARY 

HISTORY 

Group  I 

(1)  Official  Bulletin,  Vol.  I,  No.  2,  Office  of  the  Chief  of  Staff,  Washington, 

D.  C.  (Especially  pp.  21-39,)  Publisher:  Army  War  College, 
Washington,  D.  C,  Free.  (An  official  outline  of  the  theory  under 
which  our  forces  are  to  be  organized  and  administered.) 

(2)  Military  PoUcy  of  the  United  States. — Upton.     May  be  obtained  from 

Supt.  of  Docs.;  paper  50  cents;  cloth  65  cents.  (A  most  valuable 
and  comprehensive  review  of  this  subject.) 

(3)  Field  Service  Regulations,   1914.     May   be   obtained   from  Supt.  of 

Docs.;  60  cents.  (A  condensed  official  statement  of  principles, 
methods,  and  details  of  military  operations.) 

(4)  Elements  of  Strategy. — Fiebeger.     Publisher:  U.  S.  Military  Academy, 

West  Point,  N.  Y.  May  be  obtained  from  Book  Dept. ;  75  cents. 
(A  short  outline,  with  historical  illustrations.) 


Group  n 

(5)  Conduct  of  War. — Von  der  Goltz;   translated   by  J.  T.    Dickman; 

Hudson  Publishing  Co.,  Kansas  City,  Mo.  May  be  obtained  from 
Book  Dept.;  $1.70.  (The  standard  work  on  this  subject,  covering 
generally  the  same  ground  as  (4),  but  more  abstractly  and 
elaborately.) 

(6)  On  War. — Clausewitz;  translated  by  J.  J.  Graham;  3  vols.;  K.  Paul, 

Trench,  Trubner  &  Co.,  1908.  May  be  obtained  from  Book  Dept. ; 
$6.60  (including  postage  and  duty).  (The  greatest  classic  on  the 
subject;  a  complete  analysis  of  the  phenomenon  of  war,  and  pro- 
found discussion  of  the  mechanism  thereof.  Written  early  in  the 
19th  Century,  it  is  still  the  foundation  of  modern  miUtary  theory.) 

(7)  American  Campaigns. — M.  F.  Steele;  2  vols.;  Publishers:  Byron  S. 


164  THE  ENGINEER  IN  WAR 

Adams  Publishing  Co.,  Washington,  D.  C.  May  be  obtained 
from  Book  Dept.;  $4.50.  (In  addition  to  careful  historical  sur- 
veys of  all  the  campaigns  from  the  Colonial  Wars  to  the  Spanish 
American  War,  these  lectures  give  extensive  and  valuable  com- 
ments as  to  the  military  principles.) 

(8)  A  study  of  Attacks  on  Fortified  Harbors. — Rodgers;  Proceedings  Nos. 

Ill,  112,  and  113,  U.  S.  Naval  Institute,  Annapolis,  Md. 

(9)  Lessons  of  the  War  with  Spain. — Mahan.     Publishers:  Little,  Brown 

&  Co.,  Boston,  Mass.  May  be  obtained  from  Book  Dept.;  S2.00. 
(Of  special  importance,  as  showing  the  true  relation  between  our 
coast  defense  and  our  navy.) 

(10)  Reports  of  Military  Observers  on  the  Russo-Japanese  War.     Part  111. 

— J.  E.  Kuhn.  May  be  obtained  from  Supt.  of  Docs.;  60  cents. 
(In  addition  to  an  account  of  operations,  this  report  contains  valu- 
able information  as  to  fortification  and  siege  work,  organization, 
and  equipment.) 

(11)  Organization  and  Operation  of  the  Lines  of  Communications  in  War. — 

Furse,  1894.     Publishers:  Wm.  Clowes  &  Sons.,  Ltd.,  London. 
(An  old  but  comprehensive  survey  of  this  subject,  with  much  his- 
torical information.) 

"B"  PERMANENT  FORTIFICATIONS 

Group  I 

(The  references  given  cover  chiefly  the  principles  and  general  features  of 
this  subject;  the  details  are  mostly  printed  in  unavailable  form,  either  in 
service  journals  or  in  confidential  documents.  References  to  some  of  the 
former  can  be  furnished,  if  desired.) 

(12)  Report  of    National   Coast    Defense    (Taft)  Board,   1906.     May  be 

obtained  from  Army  War  College,  Washington,  D.  C.  Froe. 
(The  official  project  for  harbor  defenses  of  the  United  States.  On 
account  of  progressive  obsolescence  of  seacoast  defenses,  this 
project  has  been,  or  is  being,  modified,  but  still  sets  forth  clearly 
the  fundamentals  of  its  subject.) 

Group  n 

(13)  Lectures  on  Seacoast  Defense. — Winslow.     Publishers:  U.  S.  Engineer 

School,  Washington  Barracks,  D.  C.  Price  50  cents.  (Much  of 
these  lectures  relates  to  technical  details,  and  a  considerable  part 
is  now  obsolete.) 


BIBLIOGRAPHY  165 

(14)  Permanent  Fortifications. — Fiebeger,  1900;  U.  S.  Military  Academy, 

West  Point,  N.  Y.;  $1.00.  May  be  obtained  from  Book  Dept. 
(While  rather  old,  this  work  gives  a  simple  presentation  of  the 
fundamentals  of  its  subject,  including  an  historical  outline.  A 
revised  edition  will  soon  be  published.) 

(15)  Fortification.— G.    S.    Clarke;   Button    &    Co.,    New    York;   $4.50. 

May  be  obtained  from  Book  Dept.  (A  treatise  on  the  same  lines 
as  (14)). 

(16)  Principles  of  Land  Defense. — Thuillier,  1902;  Longmans,  Green  &  Co. 

May  be  obtained  from  Book  Dept.;  $3.83.  (A  very  valuable 
work,  covering  the  principles  of  both  field  and  permanent  forti- 
fication.)   (Probably  the  best  single  work  on  the  subject. — P.  S.  B.) 

"C"  ORGANIZATION,  EQUIPMENT,  AND  DUTIES  OF 
ENGINEER  TROOPS 

Group  I 

(17)  Field  Service  Regulations,  1914.     (See  "A"  3.) 

(18)  Tables  of  Organization,  1914.     May  be  obtained  from  Supt.  of  Docs.; 

25  cents.  (These  tables  represent — subject  to  modification  and 
within  the  limits  of  existing  law — the  approved  policy  of  the  War 
Department  with  regard  to  organization.) 

(19)  Official  Bulletin,  Office  of  the  Chief  of  the  Staff,  Vol.  I,  No.  4  (Ap- 

pendix 4.)  Use  of  Engineer  Troops.  Publisher:  Army  War  Col- 
lege, Washington,  D.  C.  Free.  (An  official  statement  of  the 
principles  which  should  govern  in  the  use  of  engineers,  with 
practical  suggestions.) 

(20)  Duties  of  Engineer  Troops  in  a  General  Engagement  of  a   Mixed 

Force — Burgess.  Publisher:  U.  S.  Engineer  School,  Washington 
Barracks,  D.  C;  25  cents.  (Obsolete  in  some  respects,  particu- 
larly organization,  but  excellent  in  general  scope.) 

(21)  General  Orders  No.  6,  War  Department,  1915.     May  be  obtained  from 

The  Adjutant  General,  U.  S.  Army,  Washington,  D.  C.  Free. 
(Prescribes  the  training  of  Engineer  troops.) 

Group  n 

(22)  Studies  in   Minor  Tactics. — Army  Service  Schools,   1915.     May  be 

obtained  from  Book  Dept.;  50  cents.  (The  principles  of  Minor 
Tactics  are  set  forth  by  solution  of  a  series  of  problems.) 

(23)  Technique  of   Modern  Tactics. — Bond  &  McDonough,   1914;  Banta 

Publishing  Co.,   Menasha,   Wis.     May  be  obtained  from  Book 


166  THE  ENGINEER  IN  WAR 

Dept.;  $2.55.  (This  work  covers,  in  a  very  specific  way,  the 
principles  of  tactics  for  all  arms,  a  general  knowledge  of  which  is 
essential  for  engineers.) 

(24)  Operation  Orders. — Von  Kiesling;  translation.     May  be  obtained  from 

Book  Dept. ;  50  cents.  (A  lucid  exposition,  by  use  of  assumed  cases, 
of  the  operation  of  highly  trained  troops  of  all  arms  in  various 
phases  of  battle.) 

(25)  Engineer  Unit  Accountability  Manual.     May  be  obtained  from  Supt. 

of  Docs. ;  5  cents.  (Official  lists  of  standard  equipment  supplied  to 
engineer  battahons  and  companies.) 

(26)  Organization  of  the  Bridge  Equipage  of  the  U.  S.  Army,  1915.     (Re- 

vised edition  just  going  to  press.)  (Includes  description  of  equi- 
page and  regulations  for  ponton  drill.) 

(27)  Officers'    Manual. — Moss;  Banta    Publishing    Co.,    Menasha,    Wis.; 

$2.50.  May  be  obtained  from  Book  Dept.  (Treats  of  routine 
duties  of  officers,  customs  of  the  service,  army  organization,  etc.) 

(28)  Manual  for  Courts  Martial.     May  be  obtained  from  Supt.  of  Docs.; 

50  cents. 

"D"  FIELD  ENGINEERING 

MiUtary  field  engineering  at  the  front  differs  from  ordinary  engineering 
work  in  the  field,  in  being  generally  simpler,  of  a  rough-and-ready  character, 
and  especially  because  of  the  limited  equipment  which  can  be  taken  along 
with  the  advance  of  an  army,  and  because  of  the  necessity  of  working  in  strict 
subordination  to  the  military  situation.  In  rear  of  the  army,  on  the  con- 
trary, conditions  are  very  similar  to  those  governing  ordinary  engineering 
operations,  and  civilian  organization  is  suitable,  subject  to  directions  by  the 
higher  military  staflf.  Little  attempt  is  made  in  works  on  military  field 
engineering  to  treat  of  general  engineering  methods.) 

(29)  Field  Fortification.— Fiebeger,  1913;  John  Wiley  &  Sons,  New  York. 

May  be  obtained  from  Book  Dept.;  $1.90.  (In  addition  to  tech- 
nical details,  this  work  gives  valuable  historical  illustrations  of  the 
principles  of  this  subject.) 

(30)  Field    Entrenchments,    Spade   Work    for  Riflemen. — John    Murray, 

London.  May  be  obtained  from  Book  Dept. ;  40  cents.  (A  very 
up-to-date  little  work;  especially  on  details.) 

(31)  Notes  on  Field  Fortification. — Army  Field  Engineer  School.     May  be 

obtained  from  Book  Dept. ;  30  cents. 

(32)  Engineer  Field  Manual. — Professional  Papers  No.  29,  Corps  of  Engi- 

neers, U.  S.  Army;  3d  edition,  1909,  500  pages.  May  be  obtained 
from  Supt.  of  Docs.,  $1.00.  (A  very  complete  official  pocketbook 
for  engineer  officers  in  the  field,  containing  much  tabular  and  tech- 


BIBLIOGRAPHY  167 

nical  data,  as  well  as  brief  outlines  of  principles  and  methods.  The 
subjects  covered  are:  Part  I,  Reconnaissance;  Part  II,  Bridges; 
Part  III,  Roads;  Part  IV,  Railroads;  Part  V,  Field  Fortification, 
and  Part  VI,  Animal  Transportation.  A  new  revision  of  the 
manual  is  contemplated,  but  will  not  be  ready  within  a  year.  The 
portion  of  the  manual  relating  to  Field  Fortification,  being  some- 
what obsolete,  should  be  considered  in  connection  with  either  (30) 
or  (31)  above.  The  portion  relating  to  Railroads  is  largely  super- 
seded by  (35)  below. 

(33)  Notes  on  Bridges  and  Bridging. — Spalding.     May  be  obtained  from 

Book  Dept.     (A  small  pamphlet  on  military  bridging.) 

(34)  Military  Topography  for  Mobile  Forces. — Sherrill,  2d  Edition;  Banta 

Publishing  Co.,  Menasha,  Wis.,  1911.  May  be  obtained  from  Book 
Dept.;  $2,25.  (Besides  matter  given  in  ordinary  text-books  on 
surveying,  this  work  gives  in  detail  the  special  methods  of  sketching 
developed  in  the  army  for  rapid  military  mapping.) 

(35)  Military  Railroads.-^Connor;  Professional  Papers  No.  32,  Corps  of 

Engineers,  U.  S.  Army;  Supt.  of  Docs.;  50  cents.  (Intended  to 
cover  general  administration  of  existing  railroads  for  military 
purposes  and  the  handling  of  railroads  by  military  personnel  in  the 
advanced  sections  where  railroads  can  not  be  operated  by  their 
regular  civilian  organizations,  or  where  new  railroads  are  required 
in  the  immediate  vicinity  of  the  Army.  Revised  edition  soon  to 
appear.) 

(36)  Notes  on  Military  Explosives. — Weaver:  J.  Wiley  &  Sons,  New  York; 

1912.  May  be  obtained  from  Book  Dept.;  $2.20.  (Elementary 
notes  on  this  subject  will  be  found  in  the  Engineer  Field  Manual 
and  other  references  cited.     This  work  is  more  elaborate.) 

"E" '  MISCELLANEOUS 

(37)  Regulations  for  the  Army  of  the  United  States;  Supt.  of  Docs.;  50 

cents. 

(38)  The  ''Volunteer  Law,"  approved  April  25,  1914;  Bulletin  No.  17,  War 

Department,  1914.  May  be  obtained  from  The  Adjutant  General, 
U.  S.  Army,  Washington,  D.  C.     Free. 

(39)  General  Orders  No.  54,  War  Department,   1914.     May  be  obtained 

from  The  Adjutant  General,  U.  S.  Army,  Washington,  D.  C.  Free. 
(Covers  examination  of  candidates  for  commissions  as  officers  of 
volunteers.) 

(40)  General  Orders  No.  50,  War  Department,  1915.     May  be  obtained 

from  The  Adjutant  General,  U.  S.  Army,  Washington,  D.  C.     Free. 


168  THE  ENGINEER  IN  WAR 

(Amends  General  Orders  54,  1914,  as  to  examination  of  candidates 
for  commissions  in  volunteer  engineers.) 

(41)  Treatise  on  Military  Law. — Davis;  J.  Wiley  &  Sons,  New  York.     May 

be  obtained  from  Book  Dept. ;  $5.30. 

(42)  Elements  of  Military  Hygiene. — Ashbume;  new  edition;  Houghton, 

Mifflin  &  Co.,  Boston,  1915.     May  be  obtained  from  Book  Dept.; 
$1.30. 

"F"  PERIODICALS 

(43)  Professional  Memoirs,  Corps  of  Engineers,  U.  S.  A.,  and  Engineer 

Department  at  Large;  Bi-monthly   (formerly  quarterly);  Wash- 
ington Barracks,  D.  C,  Engineer  Press;  per  year,  $3.00. 

(44)  The  Royal  Engineers*  Journal. — Royal  Engineers'  Institute,  Chatham, 

England;  Monthly;  per  year  $4.00.     (American  agents,  E.  Steiger 
&  Co.,  49  Murray  St.,  New  York.) 

(45)  Journal  of  the  Military  Service  Institution,  Governors  Island,  New 

York.    Bi-monthly;  published  by  the  Institution;  per  yaer  $3.00. 

(46)  Journal  of  the  United  States  Artillery;  Bi-monthly;  Fort  Monroe,  Va., 

Coast  Artillery  School  Press;  per  year  $2.75,  including  Index  to 
Current  Literature;  without  Index,  $2.50. 

(47)  Journal  of  the  United  States  Cavalry  Association;  published  by  the 

Association  at  Fort  Leavenworth,  Kans.;  per  year  $2.50. 

(48)  Infantry  Journal;  Bi-monthly;  published  by  the  U.  S.  Infantry  Asso- 

ciation, Union  Trust  Building,  Washington,^  D.  C;  per  year  $3.00. 

(49)  Field  Artillery  Journal;  quarterly;  published  by  the  U.  S.  Field  Artil- 

lery Association,  601  Star  Building,  Washington,  D.  C;  per  year 
$3.00. 


In  addition  to  the  foregoing  list,  issued  by  the  War  Dept.,  the  following 
text-books  will  be  found  of  interest: 

(50)  The   Nation  in   Arms.— Von  der   Goltz.     Book   Dept.,   $2.50.     (An 

exposition  of  the  modem  theory  of  war,  very  readable  and  inter- 
esting.) 

(51)  Letters  on  Applied  Tactics  (with  maps). — Griepenkerl.     Book  Dept., 

$1.70.     (A  standard  German  work  on  minor  tactics,  the  principles 

being  well  presented  by  a  series  of  problems  and  solutions.) 
(52)'Dutics  of  the  General  Staff.— Von  Schellendorf.     Book  Dept.,  $1.85. 

(A  German  work  probably  the  best  on  this  subject.) 
(53), The  Rifle  in  War.— Eames.     Book  Dept.,  $1.70.     (A  theoretical  and 

practical  investigation  of  the  effects  of  rifle  fire  in  battle.) 
(54)  Manual  of  Military  Field  Engineering. — Beach.     Book  Dept.,  90  cents. 

(For  many  years  the  best  American   manual.     It  is  now  largely 


BIBLIOGRAPHY  169 

superseded  by  the  Engineer  Field  Manual  (32)  but  is  still  of 
interest  and  value.) 

(55)  Examination  and  Repair  of  Simple  Highway  Bridges. — Sherrill.     (A 

pamphlet  of  the  Book  Dept.) 

(56)  Military  Demolitions. — MacArthur.     (A  pamphlet  of  the  Book  Dept.) 

(57)  Individual    and    Combined    Military   Sketching. — Cole    and    Stuart. 

Book  Dept.,  95  cents.     (Describes  the  methods  for  hasty  mapping 
of  relatively  large  areas  under  war  conditions.) 


GLOSSARY 

OF 

MILITARY  TERMS  EMPLOYED  IN  THE  TEXT 

Abattis. — An  obstacle  consisting  of  felled  trees,  often  interlaced  with  wire. 
The  trees  are  felled  or  placed  with  their  tops  toward  the  enemy. 

Applicatory  method. — A  system  of  military  peace  training  by  means  of 
the  solution  of  practical  problems  in  strategy  and  tactics.  These  problems 
are  solved  on  a  map  or  on  the  terrain,  and  are  called  ''map  problems"  and 
**  terrain  exercises." 

Artillery. — The  heavier  pieces  of  ordnance,  as  distinguished  from  small- 
arms  and  machine  guns.  Artillery  includes  guns,  howitzers  and  mortars  of 
various  calibers.  All  modern  artillery  is  rifled.  Mobile  artillery  is  habitu- 
ally mounted,  both  for  transport  and  use,  on  wheeled  carriages,  and  accom- 
panies the  mobile  troops. 

Balk. — A  bridge  stringer.  Commonly  applied  to  the  stringers  of  the 
ponton  equipage. 

Battalion. — A  unit  of  army  organization  consisting  of  several  companies, 
usually  four. 

Bomb-proof. — A  shelter,  usually  subterranean,  against  high-explosive 
shell. 

Chess. — The  deck  plank  of  the  portable  bridge  equipage. 

Chevaux-de-frise. — An  o!)stacle  in  the  form  of  a  saw-horse  with  several 
legs. 

Clinometer. — A  small  hand  instrument  used  to  measure  the  inclination 
or  slope  of  the  ground. 

Communications. — The  prepared  routes  by  which  troops  move  from 
one  part  of  a  position  to  another;  also  their  lines  of  supply  and  reinforce- 
ment. The  term  is  also  applied  to  telegraph,  telephone  and  other  signalling 
apparatus. 

Concentration  camp. — A  camp  at  which  troops  are  assembled  for  purposes 
of  training. 

Corduroy. — Logs  or  slabs  laid  crosswise  to  form  a  road  on  swampy  ground. 

Counter-attack. — Offensive  operations  by  troops  whose  general  attitude 
is  or  has  been  defensive. 

Counter-mining. — The  subterranean  operations  of  troops  on  the  defensive 
for  the  purpose  of  frustrating  the  efforts  of  the  attack. 

170 


GLOSSARY  171 

Cover. — Protection  from  fire  and  view. 

Declinator. — A  magnetic  needle  attached  to  the  edge  of  a  sketching  board 
for  the  purpose  of  orientation. 

Defensive  position. — A  line  or  belt  of  the  terrain  occupied  by  troops  and 
prepared  for  defense  by  means  of  field  fortifications. 

Delaying  action. — A  combat  entered  into  for  the  purpose  of  temporarily 
delaying  the  enemy. 

Demolition. — The  destruction  of  material  objects  by  any  means. 

Detonator. — A  small  charge  of  explosive  used  to  ignite  a  larger  charge. 

Division. — A  unit  of  army  organization,  the  smallest  which  includes  all 
branches  of  the  service.  In  the  United  States  Army  a  division  has  a  strength 
of  about  20,000.  It  includes  infantry,  cavalry  and  field  artillery  and  the 
necessary  special  troops  such  as  engineers,  signal,  medical  and  sanitary,  etc., 
with  all  the  requisite  wagon  or  motor  transport. 

Enfilade. — Fire  from  the  flank,  parallel  or  nearly  parallel  to  the  line  against 
which  it  is  directed.  It  is  peculiarly  eflfective  and  demoralizing  and  is 
always  carefully  guarded  against. 

Estimate  of  the  situation. — A  mental  review  of  existing  conditions  and 
circumstances  on  which  a  commander  bases  his  plans. 

Fascine. — A  long  cyhndrical  bundle  of  brush  used  as  a  revetment. 

Fire  superiority. — Superior  moral  or  physical  fire  effect  as  compared  to 
that  of  the  adversary.  Fire  superiority  is  implied  if  the  assailant  can  ad- 
vance or  force  back  the  defender.  Fire  superiority  for  the  defender  is 
implied  if  he  can  hold  his  ground  and  check  the  advance  of  the  assailant. 

Fixed  ammunition. — Ammunition  in  which  the  projectile  and  propelling 
charge  are  a  single  piece,  the  charge  being  contained  in  a  metal  case  with  the 
projectile  fixed  in  the  end  like  a  rifle  cartridge.  It  is  used  in  all  small  arms 
and  machine  guns  and  in  many  of  the  smaller  field  guns  and  howitzers. 

Flanks. — The  extremities  of  a  defensive  line  and  the  ground  in  their 
vicinity. 

Flying  ferry. — A  ferry  in  which  the  float  is  swung  from  bank  to  bank  by 
means  of  a  line  anchored  upstream. 

Fortification. — Any  engineering  work  or  accessory  device  which  increases 
the  fighting  power  of  troops  by  affording  shelter  or  concealment  or  increased 
fire  effect,  or  which  restricts  the  tactical  maneuvers  or  fire  effect  of  the  enemy. 

Fortification,  field  or  hasty. — Those  works  executed  by  combatant  troops 
in  the  field  to  meet  immediate  tactical  needs. 

Fougasse. — A  small  land  mine  with  a  charge  of  explosive  and  broken 
stone.     It  is  fired  by  powder  fuse  or  electricity  as  the  enemy  approaches. 

Fuse. — A  device  used  for  detonating  the  explosive  charge  of  a  shell  or 
shrapnel.  Fuses  are  classified  as  time,  percussion,  combination  (percussion 
and  time)  and  delayed  action.     Time  fuses  detonate  at  the  end  of  a  given 


172  THE  ENGINEER  IN  WAR 

time,  percussion  fuses  on  impact.  A  delayed  action  fuse  is  one  which  delays 
the  explosion  of  the  charge  until  the  projectile  has  penetrated  the  structure 
which  it  strikes.  The  term  fuse  is  also  applied  to  powder  trains  used  to 
ignite  placed  charges  of  explosive  in  demolition.  Electric  fuses  are  devices 
which  detonate  a  charge  by  means  of  the  heating  efifect  of  an  electric  cur- 
rent.    They  are  also  called  primers. 

Gabion. — A  hollow  cylinder  of  brush  or  other  material  which  is  filled  with 
earth  and  used  as  a  revetment. 

General  Staff. — A  corps  of  highly  trained  officers  charged  with  the  study 
of  the  conduct  of  war  and  the  detailed  methods  of  military  operations.  In 
time  of  war  they  direct  and  administer  the  operations  of  mobilization,  con- 
centration, supply,  transportation,  etc.,  and  assist  the  field  commanders  in 
planning  and  executing  their  operations. 

Grenade. — A  charge  of  high  explosive  in  a  container  hurled  a  relatively 
short  distance  by  hand  or  by  means  of  a  catapult,  rifle,  or  small  mortar. 
The  charge  explodes  by  time-fuse  or  on  impact.  Large  grenades  are  called 
air-mines  or  air-torpedoes.  They  are  distinguished  from  high  explosive  shell 
by  their  relatively  short  range,  which  ordinarily  does  not  exceed  500  yards. 

Gun. — A  piece  of  ordnance  fired  from  a  platform  or  wheeled  mount.  A 
gun,  as  compared  with  a  howitzer,  has  a  relatively  long  barrel,  flat  trajectory 
and  high  velocity.  Its  effect  is  produced  largely  by  the  vigor  of  the  blow 
struck  by  the  projectile,  which  may  be  combined  with  the  action  of  a  charge 
of  explosive.  Guns,  according  to  their  size  and  uses,  are  classed  as  moun- 
tain, light  or  heavy  field,  siege  and  seacoast.  All  modern  guns  are  breech- 
loading  rifles.  ^ 

Head  cover. — A  vertical  shield  of  any  material  which  protects  the  heads 
of  tlie  troops  from  fire. 

High  explosive  shell. — A  projectile  containing  a  charge  of  high  explosive 
fired  from  a  gun  or  howitzer.  The  charge  explodes  by  time  fuse  or  upon 
impact.  It  is  used  principally  to  demolish  material  objects,  such  as  fortifi- 
cations, and  is  seldom  employed  against  troops  in  the  open,  being  for  this 
purpose  less  effective  than  shrapnel. 

Howitzer. — A  piece  of  ordnance  having,  as  compared  with  a  gun,  a  short 
barrel  and  curved  trajectory.  Its  effect  is  produced  chiefly  by  the  explosion 
of  the  charge  contained  in  the  projectile.     (See  mortar.) 

Hurdle. — A  revetment  of  woven  brush. 

Initiative. — A  commander  is  said  to  have  the  initiative  when  he  carries 
out  a  preconceived  plan,  dictating  and  controlling  the  course  of  operations 
and  forcing  the  adversary  to  meet  his  lead.  The  initiative  is  ordinarily, 
though  not  always,  possessed  by  the  attacker,  inasmuch  as  he  usually  selects 
the  time,  place  and  manner  of  attack,  and  forces  the  defender  to  adapt  his 


GLOSSARY  173 

measures  to  meet  it.  A  vigorous  counter-attack,  which  forces  a  suspension 
of  the  attack,  transfers  the  initiative  to  the  original  defender. 

Latrine. — A  dry  sewage  pit  or  trench;  a  cesspool. 

Line. — A  general  term  applied  to  all  combatant  troops;  a  position  occupied 
by  troops,  as  a  defensive  line. 

Line  of  investment. — A  cordon  of  troops  drawn  around  a  fortress  for  the 
purpose  of  cutting  off  its  supply  and  communication;  usually  the  first  step 
in  siege  operations. 

Listening  galleries. — Subterranean  galleries  driven  to  the  front  for  the 
purpose  of  detecting  the  mining  operations  of  the  enemy. 

Listening  posts. — Sheltered  positions  in  advance  of  a  defensive  line  for  the 
purpose  of  early  detection  of  the  enemy's  movements.  They  are  connected 
with  tlie  main  line  by  a  communicating  trench  or  subterranean  gallery. 

Loop-holes. — Openings  in  a  parapet  or  head  cover  through  which  fire  is 
delivered. 

Machine  gun. — An  automatic  or  semi-automatic  gun  of  small  caliber 
capable  of  great  rapidity  of  fire.  It  uses  fixed  ammunition,  preferably 
identical  with  that  emf)loyed  in  small  arms.  The  ammunition  is  fed  auto- 
matically from  a  hopper,  clip  or  belt. 

Maneuver. — A  movement  of  a  body  of  troops.  Strategical  maneuvers 
include  movements  of  troops,  on  a  relatively  large  scale,  in  preparation  for 
prospective  battle,  but  usually  at  a  distance  from  the  enemy.  Tactical 
maneuvers  include  movements  executed  on  the  battlefield  or  in  the  near 
presence  of  the  enemy.  As  compared  with  strategical  maneuvers  they  are 
usually  on  a  smaller  scale,  in  closer  proximity  to  the  enemy,  and  more  im- 
mediately related  to  battle  tactics. 

Map  distance. — The  horizontal  interval  between  contours  (on  the  map) 
corresponding  to  a  given  slope  or  gradient. 

Mining. — The  operations  of  subterranean  attack. 

Mobility. — The  power  of  rapid  movement.  Mobile  troops  are  those 
capable  of  quickly  changing  their  location  and  dispositions  to  meet  tactical 
needs.  Non-mobile  troops  are  capable  only  of  passive  defense.  It  is  there- 
fore essential  that  first-line  troops  shall  be  highly  mobile.  Otherwise  they 
can  not  seize  or  retain  the  initiative.  Even  in  defensive  operations  mobility 
is  essential  to  mfeet  the  movements  of  the  assailant. 

Mobilization. — The  change  from  peace  to  war  footing.  An  army  is  said 
to  be  mobilized  when  it  is  assembled,  armed  and  equipped,  and  organized 
to  take  the  field. 

Morale. — The  collective  psychological  condition  or  spirit  of  troops,  espe- 
cially combatant  troops  engaged  in  battle.  High  morale  is  implied  when 
troops  respond  readily  to  the  will  of  their  commander.  Morale  is  therefore 
measured  by  the  extent  to  which  troops  submit  to  the  control  of  their  officers. 


174  THE  ENGINEER  IN  WAR 

Mortar. — A  piece  of  ordnance  having  a  very  short  barrel  and  curved 
trajectory.  It  throws  a  projectile  containing  a  large  charge  of  high 
explosive. 

Normal  system. — A  system  of  scales  and  contour  intervals  so  arranged 
that  a  certain  map  distance  represents  the  same  slope  whatever  the  scale  of 
the  map. 

Observation  posts. — (See  listening  posts.)  Observation  posts  may  also 
occupy  commanding  positions  in  rear  of  the  firing  line. 

Obstacle. — Any  device  which  retards  the  enemy's  movements  without 
affording  him  shelter  from  fire. 

Ordnance. — A  collective  term  applied  to  all  firearms  which  hurl  projec- 
tiles. As  generally  used  the  term  excludes  "small  arms,"  such  as  rifles  and 
pistols,  and  applies  especially  to  the  heavier  pieces.  (See  small-arms  and 
artillery.) 

Outpost. — A  line  of  observation  and  resistance  established  between  a  body 
of  troops  and  the  known  or  supposed  position  of  the  enemy  to  guard  against 
surprise  attacks. 

Overhead  cover. — A  horizontal  or  inclined  shield  of  any  material  which  ex- 
tends over  tlie  heads  of  the  troops  and  protects  them  from  high  angle  fire. 

Pace  tally. — An  instrument  for  counting  paces. 

Pack  train. — .\  train  of  animals,  usually  mules,  carrying  packs  on  saddles. 
This  form  of  transportation  is  used  in  mountainous  country  or  wh§re  roads 
are  very  poor. 

Parados. — A  bank  of  earth  in  rear  of  a  trench  to  protect  the  occupants 
from  the  back  draft  of  shells  bursting  behind  the  trench. 

Parapet. — A  bank  of  earth  or  other  material  in  front  of  a  trench  or  em- 
placement which  protects  the  occupants  from  fire. 

Pioneer. — A  member  of  the  mobile  engineer  forces  of  an  army. 

Plane  table,  military. — A  small  plane  table  or  sketching  board  used  in 
military  mapping. 

Ponton. — A  portable  boat  used  as  a  support  or  pier  for  a  floating  bridge. 

Ponton  equipage. — The  portable  floating  bridge  equipment  of  an  army. 

Principal  sketcher. — One  who  coordinates  and  controls  the  work  of  a 
number  of  individuals  in  combined  sketching. 

Reconnaissance. — A  rapid  examination  of  a  structure,  locality,  district, 
etc.,  for  the  purpose  of  noting  features  and  gathering  information  of  military 
value. 

Reserves. — Troops  temporarily  withheld  from  action  for  the  purpose  of 
reinforcement  at  critical  times  and  places.  Also  individuals  who  have 
undergone  military  training  and  are  aoailahle  for  service  but  not  at  the  time 
a  part  of  the  standing  army. 


GLOSSARY  175 

Revetment. — Any  device  used  to  hold  earth  or  other  material  at  a  slope 
steeper  than  the  natural  slope. 

Shrapnel. — A  projectile  containing  a  number  of  small  bullets  or  fragments 
with  a  propelling  charge.  It  explodes  in  the  air  and  scatters  the  bullets 
and  fragments  of  the  case  over  a  considerable  area,  being  in  effect  a  flying 
shotgun.  The  shrapnel  of  the  3-in.  U.  S.  field  gun,  when  properly  burst, 
will  sweep  an  area  200  to  300  yards  in  depth  and  20  to  25  yards  in  width, 
killing  or  seriously  wounding  any  man  or  animal  in  the  area.  It  has  little 
effect  on  fortifications  and  is  used  only  against  troops.  Shrapnel  is  hence 
known  as  the  "man-killing  projectile." 

Siege. — The  formal  investment  and  attack  of  a  fortress. 

Sketch,  area  or  position. — A  hasty  military  map  of  an  area  of  ground  ** 
showing  the  contours  and  all  natural  and  cultural  features  of  military 
significance. 

Sketch,  landscape. — ^A  pictorial  representation  of  a  landscape. 

Sketch,  military. — A  term  applied  to  a  hastily  constructed  map  prepared 
in  tho  field  for  military  uses. 

Sketch,  place. — An  area  sketch  executed  from  a  single  station  where  the 
sketcher  does  not  have  access  to  the  terrain  portrayed. 

Sketch,  road. — A  hasty  map  showing  the  route  of  a  road  and  the  nearby 
topography. 

Sketching  board. — See  plane  table. 

Sketching,  combined. — Military  mapping  in  which  an  area  is  divided 
into  sections  to  be  mapped  by  individuals,  the  results  being  subsequently 
combined. 

Sketching,  individual. — Military  mapping  operations  where  each  indi- 
vidual operates  independently. 

Small-arms. — Firearms,  such  as  rifles  and  pistols,  carried  by  individuals. 
The  term  is  occasionally  applied  also  to  machine  guns  which  use  small-arms 
cartridges. 

Spar  bridge. — A  type  of  military  bridge  in  which  the  support  consists  of 
two  trestles  which  are  tilted  toward  each  other  and  locked  together. 

Splinter-proof. — A  shelter  similar  to  a  bomb-proof  but  designed  to  afford 
protection  only  against  rifle  bullets,  shrapnel  and  shell  fragments.  It  is 
not  proof  against  penetration  by  large  projectiles. 

Strategy. — The  application  of  the  broad  fundamental  principles  of  the 
art  of  war.  The  object  of  strategy  is  to  place  troops  in  the  most  favorable 
or  least  unfavorable  position  for  battle,  which  is  the  culmination  of  strategy. 
Strategy  deals  with  questions  of  national  policy,  national  resources,  geogra- 
phy, mobilization  and  concentration  of  troops,  supply,  transportation,  etc. 

Supports. — Troops  held  in  rear  of  the  firing  line  for  the  purpose  of  replac- 
ing losses. 


176  THE  ENGINEER  IN  WAR  j 

Tactics. — The  methods  employed  in  handling  troops  in  battle  or 
immediate  preparation  therefor. 

Terrain. — An  area  of  ground  considered  as  to  its  extent  and  topograp  | 
in  relation  to  its  use  for  a  specific  purpose,  as  for  a  battle  or  the  erection  | 
fortifications.  ' 

Theater  of  war. — The  territory  covered  by  the  operations  of  belligef 
forces. 

Trajectory. — The  path  of  a  projectile.  Guns  of  high  power  are  said 
have  a  flat  trajectory,  that  is  to  say,  one  which  approaches  a  straight  linf 

Traverse. — A  bank  of  earth  or  other  material  in  rear  of  and  perpendicu 
to  the  parapet  for  the  purpose  of  protecting  the  occupants  from  oblique 
enfilade  fire  and  to  localize  the  effect  of  shells  bursting  in  the  trench. 

Trenches. — The  purpose  of  trenches  is  to  protect  the  troops  occupy] 
them  from  hostile  fire.  According  to  their  use  they  are  classified  as  fij 
support  and  communicating  trenches. 

Wire  entanglement. — An  obstacle  of  wire  or  barbed  wire  strung  on  po 
or  other  supports;  the  most  commonjy  employed  obstacle. 


INDEX 


(Bold   face   figures    denote   general  treatment  of  subjects.) 


bbatis,  93 

abutment  sills — see  Bridges,  43 
ctinic  printing  processes,  127 
ilignment,  of  roads,  64,  66,  67,  68 
inchorage — ponton  bridges,  37,  43 
inchorages — suspension  bridges,  53 
meroid  barometer,  69,  118,  120,  126 
mgles,  measurement  of,  118,  119 
kpplicatory  system  of  military  in- 
struction, 158,  159,  160 
Lrclies — demolition,  112 
^rca  or  distance  sketched  in  a  day, 

126 
Artillery,  57,  61,  73,  74,  76,  96,  101, 

102,  .03,  106,  131 
Usault  of  sic  t^e  works,  100,  104 
Atlantic  seaboard: 

industries  and  population,  7 
probable  theatre  of  war,  7 
Uitomobiles-  see  Motor  trucks. 

Balk  of  ponton  equipage,  37,  43 
Bamboo  bridges,  48 
Barometer,  aneroid,  69,  118,  120,  126 
Battlefield,  illumination  of,  94,  96 
enham.  Gen.  H.  W.,  quoted,  44,  45 
ismarck,  3 
oiling  of  water,  139 
ombardment  of  a  fortress,  103 
[Bombs,  illuminating,  96 
Bomb-proof  shelters,  84 
Bridges,  15,  19,  20,  22,  26,  36,  122, 
125,  131 
bamboo,  48 
12  177 


Bridges,  bracing  of,  47,  48 

combination  of  types,  54,  56 

crib,  49 

deck  or  roadway  of,  37,  56,  60,- 
61 

demolition,  110,  112    , 

examination  of,  60 

existing,  22,  46,  60 

factor  of  safety,  40,  60,  61 

false  work,  49 

formula)  for  strength  of,  60 

improvised,  35,  46 

lashings  for,  38,  56 

materials  for,  35,  45,  48 

pile,  48 

pile  drivers,  33,  48 

placarding,  62 

ponton,  29,  31,  37 
abutments,  43 
anchorage,  37,  43,  44 
balk  or  stringers,  37,  43 
buoyancy  of  pontons,  37,  38 
chess,  37 

dismantling  bridge,  43 
draw  spans  in,  44 
ferriage,  57 
historical  example  of  use,  44, 

45 
improvised  supports,  44 
light  and  heavy,  37,  38 
methods  of  construction,  40, 

41 
ponton  boats,  37,  38 
saddle,  37 


178 


INDEX 


Bridges,  ponton,  span,  38 

time  of  construction,  38,  40, 

44,  45 
transportation,  38,  40 
trestle  spans,  37,   43,   56 
weights  or  equipage,  40 
width  of  deck,  38 
portable — see  Ponton,  37 
selection  of  site,  47 
spar,  50,  51 
standard  design  in,  62 
strength  of,  60 
strengthening  and  repair  of,  46, 

62 
stringers,  37,  47,  56,  60,  61,  62 
suspension,  62 
anchorages,  53 
cables,  52 

construction,  53,  54 
hangers,  52,  54 
^  materials  employed,  52,  53 

oscillation,  54 
sag  of  cables,  53 
span,  52 
stiffening,  54 
towers,  53 
undulation,  54 
trestle,  47,  48,  56 
truss,  49,  50,  56 
use  of  existing,  22,  46,  62 
Buildings,  111,  122,  125 
Business  men's  camps,  155 
Buoyancy  of  pontons,  38 

Cables,  suspension  bridge,  52,  53 
Camps : 

concentration,  138 

epidemics,  136 

instruction,  155 

location  of,   15,   125,    131,    137, 
138 

sewage  disposal,  137,  140 


Camps,  water  supply,  131,  137 

Caps,  107 

Cesspools,  140 

Chemical  purification  of  water,  139 

Chess,  37 

Chevaux-de-frise,  93 

China,  military  policy  of,  2,  4 

Cholera,  138,  139 

Citizenship,  military  obligations  of, 
2,  3,  163 

Civil  engineering,  relation  to  mili- 
tary engineering,  11,  17 

Civil  population  of  a  fortress,  needs 
of  in  war,  102,  146 

Civilian  specialists  in  war,  17,  33,  116 

Clinometer,  69,  119 

Commandeering  supplies,  144,  148 

Commercial   standards,    conformity 
to,  144 

Commissions  in  volunteer  engineers, 
160 

Communications — see  Lines  of  com- 
munication, 74,  131 

Compulsory  service  in   Great   Bri- 
tain, 5 

Compulsory  training: 
in  Germany,  3 

prejudice    against    in     United 
States,  4,  5 

Concealment,  74,  76,  85,  86 

Concentration  of  force,  72,  73 

Concrete  mixers,  26,  33 

Conditions  governing  military  con- 
struction, 33 

Contours— see  Maps,  119,  120,  127, 
130 

Contractors,  9,  10,  22,  152,  153 

Contractors'  foremen,  153 

Control  in  mapping  and  sketching, 
116,  121,  127,  130 

Conventional  signs  in  mapping,  122 

Corduroy  roads,  66 


INDEX 


179 


Correspondence  courses  for  civilian 

engineers,  157,  158 
Cost  of  engineering  structures,   17, 

18,  19,  20 
Cost  of  warfare,  18 

excessive,  of  wars  of  U.  S.,  18 
Counter  attack,  76 
Countermining,  104 
Courses  of  instruction  for  civilian 

engineers,  156,  157 
Cover : 

artillery,  96 
reserves,  76,  87 
supports,  74,  76,  86 
Cover,  natural,  advantages  of,  86 
Crib  bridges,  49, 
Critical  points  in  mapping,  121,  127, 

130 
Culverts,  70 

Decisive  action,  selection  of  position 

for,  75 
Deck  or  roadway  of  bridges,  36,  37, 

38,  56,  60,  61 
Defensive  policy,  effect  of  on  war- 
fare, 7 
Defensive  position,  25,  74,  75,  76, 

125,  131,  137 
Delaying  action,  position  for,  75 
Demolition,  15,  74,  92,  99,  106 
arches,  112 
bridges,  110,  112 
buildings,  111 
by  explosives,  74,  99,  106 
by  fire,  106,  109,  110,  112 
by  high  explosive  shell,  74,  78, 

106 
canal  locks,  112 
framed  structures,  110 
obstacles,  112 
outfits  for,  106 
railroads,  109,  110,  111 


Demolition,    railroad,  bridges,   109, 
110 
rolling  stock.  111 
track,  109,  110,  111 
tunnels,  110 
reconnaissance  for,  108 
roads,  110,  111 
supplies  and  materials,  112 
telegraph  lines,  111 
woods,  112 
Depths,  practicable,  of  fords,  57 
Detonators,  107 
Diseases : 

epidemic,  136 
waterbome,  138 
Distance  or  area  covered  by  sketcher 

in  a  day,  126 
Distances,  measurement  of,  117 
Distillation,  139 
Drainage: 

bomb-proofs,  88 
camp  sites,  131,  137,  138 
roads,  66,  70 
trenches,  82 
Drainage  lines  in  mapping,  121,  127, 

130 
Draw  spans  in  ponton  bridges,  44 
Dressing  stations,  74 
Drills,  portable,  33 
Duties  of  engineers  in  war  defined 

— see  Engineer  troops,  13 
Dynamite,  107 
Dysentery,  138 

Economics  of  military  engineering, 
11,  17,  18,  19,  20,  21,  26,  33 

Economics   of   military   road   loca- 
tion, 68,  69,  71 

Economics  of  peace  and  war  com- 
pared, 12,  17,  18,  19,  20 

Economic  span : 

trestle  bridges,  47 


180 


INDEX 


Economic  span,  truss  bridges,  50 
Effect  of  war  on  industrj',  146,  147 
Elevations,   determination   of,    118, 

119,  120,  121 
Enfilade,  89,  100 
Engineering  colleges,  155 
Engineer  officers  for  staflf  duty,  8 
Engineer  troops: 

equipment,  28 

in  national  guard,  8 

in  regular  army,  8,  9 

needed  in  case  of  war,  7 

proportion  of,  7 
Engineer  troops,  duties  of,  13 

field  fortification,  74,  75 

Unes    of    communication    and 
bases,  7,  9,  13 

mapping,  114,  126 

mobile  army,  7,  9,  13,  16,  25 

siege  operations,  13 

sanitation,  136 
Engineering  societies,  154 
Entanglements,  wire,  93,  112 
Epidemic  diseases,  136,  138 
Equipment     for     mobile     engineer 

troops — 8€e  Tools,  26 
Equipment  of  industrial  plants,  144, 

145 
Estimation  of  slopes  and  distances, 

114,  121 
Examination  of  bridges,  60 
Expeditionary  forces  which  might  be 

landed  in  U.  S.,  6 
Exploders,  magneto-electric,  107 
Explosives,  64,  69,  74,  92,  99,  106 

requirements  for  military  uses, 
107 
Explosives  employed  in  demolition, 
107 

dynamite 

fulminates 

gun-cotton 


Explosives,  gun-powder 
jovite 
lyddit« 
melinite 
nitro-glycerine 
shimose 

Sprengel  mixtures 
trinitrotoluol 

Factor  of  safety  of  bridges,  40,  60,  61 
False  work  for  bridges,  49 
Fascines,  57 
Federal  control : 

prices  and  sales,  149 

transportation,  148 
Federal,  state,  and  municipal  em- 

ployees,  155 
Ferries,  19,  57,  58 
Field  fortification,  72 

concealment  in,  85 

correct  tactical  employment,  71 

purposes  of,  73,  74 

works  included  under,  74 
Field  of  fire,  76,  131 
Fortification,  tactical  or  hasty — «« 

Field  fortification. 
Filters,  139 
Fire  superiority,  76 
Fire,  use  of  in  demolition,  106,  109 

110,  112 
Flanks,  76,  131 
Flies,  138,  140 
Floor  or  deck  of  bridges : 

strength,  60,  61 

width,  38,  56 
Foreground : 

illumination  of,  92,  93 

preparation  of,  92,  93 
Fords,  66,  125,  131 

practicable  depths,  57 
Formulae  for  strength  of  bridges,  tiO 
61,  62 


INDEX 


181 


Fortification — see  Field  fortification, 

14,  72 
Fortification : 

effect  of  weapons  employed,  74 

purpose  of,  74 
Fortress,  siege  of,  100 
Fougasses,  94,  95 
Framed  structures,  110 
French,  Sir  John,  quoted,  151 
Fulminates,  107 
Fuse: 

instantaneous,  107 

time,  107 

rates  of  burning,  107 

Galleries : 

listening,  92 

subterranean,  89,  .92 
General  staff: 

Germany,  3 

United  States,  4,  6,  143 
Geological  Survey,  maps  of,  115,  116 
Germany : 

compulsory  regular  training,  3 

general  staff,  3 

military  policy,  3,  4,  7 

mobilization  of  resources,  3 
Gradients,  of  military  roads,  67,  68, 

131 
Gravel  for  roads,  66 
Great   Britain,    compulsory   service 

in,  5 
Grenade  nets,  82 
Grenades,  82,  84 
Gun-cotton,  107 

Head  cover,  80,  81 
Hectograph,  127 
Hoists,  portable,  33 
Hostile  interference  with  industry, 
146 


Howe  truss,  50,  62 
Hygiene,  137 

Ice,  supporting  power,  57 
Illumination  of  the  battle-field,  92, 

93,94 
Improvised  bridges,  45 
Improvised  floats,  44 
Incineration,  140 
Industrial  personnel,  144,  146,  147, 

148,  153 
Industrial  plants,  142 
Industrial  resources,  mobilization  of 

3,  142 
Information  conveyed  by  maps,  122, 

125,  126,  131 
Initiative,  72 
Instruction,  applicatory  system  of, 

158,  159,  160 
Instruction  camps,  155,  156,  157 
Instructions  for  fabrication  of  mate- 
rial, 146 
Instruments  employed  in  surveying 
and  sketching  and  in  road 
location : 
alidade,  117,  118 
aneroid  barometer,  69,  118, 120, 

126 
clinometer,  69,  119 
compass,  118 
declinator,  116 
hand-level,  120 
pace  tally,  117 
plane   table — sketching   board, 

116 
sextant,  118 
transit,  69 
Intrenching  tools,  27,  28,  29 
Intrenchments — see   Field  fortifica- 
tion. 
Inundations,  93 
Investment  of  a  fortress,  101,  102 


182 


INDEX 


Kitchen  waste,  138,  140 

Lashings,  30,  38,  56 

Latrines,  74,  140 

Line  of  investment,  102 

Lines  of  communication,  7,  9, 13,  26, 
33 

Lining  for  shafts  and  galleries,  89,  90, 
92 

Listening  galleries,  92 

Lithography — see  Map  reproduction. 

Local  resources,  13,  15,  26,  29,  125 

Location  of  military  roads,  64 

Location  of  supports,  86 

Location  of  works  of  field  fortifica- 
tion, 15,  26,  74,  75,  99 

Loopholes,  80,  85 

Lyddite,  107 

Machine  guns,  73,  74,  96,  101 
Maintenance  economics  of  military 

roads,  71 
Maintenance  of  roads,  64,  71 
Makeshifts,   characteristic   of  mili- 
tary   engineering,    12,    16, 
18,  19,  21,  141 
Manufactories,  location  of  in  U.  S., 

146 
Manufacturers'  organizations,   145, 

148 
Map  problems,  158 
Map  reading,  114,  130 
Maps,  military,  14,  15,  113 

collection,   compilation,   repro- 
duction, 14,  15,  114,    126 
127 
construction       of       contoured 

maps,  119,  120,  127,  130 
control,  116,  121,  127,  130 
conventional  signs,  122 
Geological  Survey,  115,  116 
information  conveyed,  122,  125, 
126,  131 


Maps,  instruments   employed,  116, 
120 
map  distances,  119 
need  of  maps  in  advance,  115 
normal  system,  121 
reproduction    methods    and 
equipment,   15,  29,  31,  32, 
126,  127 
road  location,  use  for,  69 
scales  for  military  purposes,  Ho 
strategical  maps,  115 
use  in  warfare,  113 
Material,  reserves  of,  29,  143 
Material  resources,  mobilization  of, 

142 
Materials     employed     in     military 
engineering,  13,  26,  29,  30, 
35,  45,  48,  49,  52,  67,  97 
Medical  department,  136 
Melinite,  107 
Mexico,  6,  35,  115 
Military  engineering,  adaptation  of 

civil  engineering,  11,  17 
Military'  obligations  of  citizenship, 

162 
Military  policy : 
China,  2,  4 
Germany,  3,  7 
Military  policy  of  United  States.  1 
Military   strength   as   distinguished 

from  resources,  1,  2 
Militar>'  training  at  colleges,  155 
Mines,  94,  95 

Mining,  military,  74,  89,  92 
Mission  controls  selection   of  posi 

tion,  75 
Mission,  defined,  158 
Mobile  army,  duty  of  engineers  witl 

13 
Mobility,  25,  28,  35,  63,  72,  86] 
Mobilization  of  industrial  personni 
146 


INDEX 


183 


Mobilization  of  material  resources — 

Germany,  3 
Mobilization  of  material  and  indus- 
trial resources,  142 

advantages  enjoyed  by  United 
States,  151 

ascertaining  probable  needs, 
142 

assistance  of  engineering  profes- 
sion, 147,  148,  150 

association  of  manufacturers, 
145,  148 

cessation  of  industry,  147 

classes  of  supplies,  143 

closing  of  markets  in  war,  147 

commandeering  supplies,  144, 
148 

conformity  to  commercial  stan- 
dards, 144 

effect  of  shortage  of  supplies  on 
military  operations,  150, 
151 

employment  of  women,  146 

equipment  of  industrial  plants, 
144 

experiences  of  European  war, 
142 

experimental  samples,  145 

federal  control  of  transporta- 
tion, 148   • 

federal  regulation  of  sales,  149 

governmental  aid,  147 

government  munition  plants, 
149 

hostile  interference,  146 

instructions  for  fabrication, 
145 

investigation  of  industrial 
plants,  144 

labor  unions,  148 

location  of  plants  on  seaboard, 
146 


Mobilization,  mobilization  of  indus- 
trial personnel,  146 
mobilization    plans    and    data, 

143,  149 
needs  of  civil  population,  146 
personnel  of  railroads,  148 
plans  and  specifications  for  war 

material,  145 
prices  for  war  material,  149 
rate  of  output,  146 
reserves  of  material,  143 
sources  of  supply,  142,  143 
stimulative  measures,  143,  145 
supplies  needed,  142 
tools,  machines  and  gauges,  145 
training  of  industrial  personnel, 

144 
transition   from   peace   to  war, 

147 
transportation     systems,     142, 

148 
United   States   self-supporting, 
147 
Mobilization  plans  and  data,   143, 

149 
Modem  theory  of  war,  2,  1 1 
Monroe  Doctrine,  6 
Motor  trucks,  30,  32,  63,  65,  143 
Mounted  section,  31 
Munition  plants: 
federal,  149 
private,  144,  145,  146 

Napoleon,  quoted,  9,  28,  35 
National  guard : 

engineer  troops  in,  8 
strength  of,  5 
training  of,  4 
Natural  features  of  terrain  utilized 

in  fortification,  86 

New     York,     engineer     troops     of 

national  guard,  8 


184 


INDEX 


Nitro-glycerine,  107 
Non-commissioned  oflBcers,  23,  130, 

153 
Normal  system  of  maps,  121 

Obligation  of  service,  2,  3,  163 
Observing  stations,  74,  131 
Obstacles,  15,  74,  76.  93,  112,  131 
Ohio,    engineer   troops   in   national 

guard,  8 
Ordnance — see  Artillery. 
Organization  of  engineer  troops,  7,  8 
Organized    land    forces    of    United 

States,  5,  8 
Orientation,  117 

Oscillations  of  suspension  bridges,  54 
Outposts,  74,  113,  131 
Overhead  cover,  81 

Pack  trains,  31 

Palisades,  93 

ParaUek,  103,  104 

Parapet,  77,  85 

Paved  highways  in  relation  to  mili- 
tary operations,  63,  64 

Personnel,  industrial,  144,  146 

Photography,  31,  127,  135 

Picrates,  107 

Pile  bridges,  48 

Pile  drivers,  33,  48,  49 

Pits,  militarj',  93 

Placarding  bridges,  62 

Place  sketch,  118 

Plane  table,  military,  116 

Plans  rarelj'  used  in  military'  engi- 
neering, 22 

Plant,  construction,  use  of  in  mili- 
tary engineering,  21,  22,  25, 
26,  32,  33 

Plant — see  Power  plants. 

Plows,  32,  64,  70 

Point  of  attack  of  a  fortress,  102 


Plattsburg  camp,  155 
Ponton  equipage — see  Bridges. 
Popular     ideas      as     to      military' 

strength,  1 
Power     plants,     portable     gasoline 

driven,  32,  33,  140 
Portable  tools,  25,  28,  29 
Pratt  truss,  50,  62 
Preparation  more  necessary   today 

than  in  past,  2 
Prevention  of  disease,  138 
Prices  for  war  material,  149 
Primers,  107 
Principal  sketcher,  126 
Profile,  132,  133 
Problems,  tactical,  150,  159 
Proportion  of  engineer  troops  with 

an  army,  7 
Purification  of  water,  139,  140 
Purposes  of  military  operations,  72 

Qualifications,   of  engineer  officers, 
9,  10,  12,  99 


Railroads,  7,  15,  26,  32,  63,  74,  109, 

110,  111,  125,  142,  148 
Rate  of  output  of  industrial  plants, 

146 
Reconnaissance,  113 
aerial,  74 

military,  14,  76,  108,  113 
Regular  army,  engineer  troops,  8 
Regular  training,  in  Germany,  3 
Repair  of  bridges,  60 
Reproduction,    map,    methods   and 

equipment,  15,  29,  31,  32, 

127 
Reserve,  trained,  3,  5,  10,  76 
Reserves  for  firing  line,  87 
Reserves  of  material,  29,  143 
Reservoirs,  139 


INDEX 


185 


Resources  of  the  state,  to  be  at  dis- 
posal of  government,  2,  3 
Resources  of  United  States,  151 
Resources  do  not  constitute 

strength,  1 
Retaining  walls,  70 
Revetments,  82 

Rifle   trenches — see   Field   fortifica- 
tion, 74,  77,  78,  80,  81,  82 
Roads,  military,  15,  63,  74,  125,  131 

alignment,  64,  66,  67,  68 

bearing  power,  66,  67,  70 

brick,  66 

corduroy,  66 

culverts,  70 

demolition  of.  111 

dragging,  71 

drainage,  70 

economics,  64,  67 

grades,  67,  68 

gravel,  66 

location,  64,  67,  68,  69 

maintenance  economics,  64,  70, 
71 

nature  of  traffic,  63,  64,  65,  67 

plant,  64,  65 

speed  of  transport,  65,  66 

surfaces,  66,  67 

switch  backs,  70 

widths,  67 
Rockets,  signalling,  96 

Saddle,  ponton,  37 

Safe  loads  of  bridges,  37,  38,  40,  60 

Samples  of  war  material,  145 

Sandbags,  80 

Sanitary  functions  of  engineers,  136, 

141 
Sanitation,  14,  15,  136 
Scales  of  maps,  115 
Scrapers,  32,  64,  70 
Searchlights,  94,  96 


Searchlights,  power  for,  96 

Security,  false  sense  of  in  United 
States,  1 

Service,  citizen's  obligation  of,  2,  3, 
163 

Selection  of  camp  sites,  133 

Septic  tanks,  140  ' 

Sewage  disposal,  137,  138,  140 

Sextant,  118 

Shear  and  chord  increments,  62 

Shell,  high  explosive,  74,  78,  84,  106, 
112 

Shelters,  bomb-  and  splinter-proof, 
74,  84 

Shiraose,  107 

Shortage  of  supplies,  effect  on  mili- 
tary, operations,  150,  151 

Shrapnel,  74,  80 

Siege  operations,  75,  100 

Siege  works,  assault  of,  100,  104 

Signal  corps,  16 

Simplicity  in  military  engineering, 
21,  28,  33,  74,  97 

Site,  selection  of  for  bridge,  47  . 

Sketches,  area  and  road — amount 
covered  in  one  day,  126 

Sketches,  military  landscape,  134, 
135 

Sketching,  military — see  Maps, 
113 

Sketching,  combined,  126 

Sky  line  or  crest,  85 

Slopes,  measurement  of,  118,  119 

Sorties,  102 

Sources  of  supply,  record  of,  143 

Spans  of  bridges — see  Bridges. 

Spar  bridges,  50,  51 

Specialists,  civilian — see  Civilian  spe- 
cialists. 

Specialization  in  military  engineer- 
ing, 15,  16,  17 

Specifications  for  material,  145 


186 


INDEX 


Speed  in  military  engineering  con- 
struction, 13,  18,  19,  20,  21, 
22,  23,  24 

Sprengel  safety  mixtures,  107 

Stimulative  measures  for  produc-: 
tion  of  munitions,  143,  145 

Strategical  fortification,  72,  100 

Strateg>^  73,  136 

Stream  crossings — see  Bridges,  fords, 
and  ferries,  36 

Strength  of  existing  liridges,  formulae, 
60,  61,  62 

Stringers,  bridge — see  Balk,  37,  47, 
56,  60,  61,  62 

Stumps,  removal,  69 

Subteiranean  attack — see  Mining,  89 

Successive  pontons,  40,  41,  43 

Superintendence  on  works  of  mili- 
tary engineering,  23,  74 

Supplies  required  by  an  army,  142 

Supports  for  firing  line,  74,  76,  86 

Surveying  instruments — see  Instru- 
ments. 

Surveying — see  Maps, 
for  road  location,  69 

Suspension  bridges,  62 

Switch-backs,  70 

Tactical    requirements    in    military 

engineering,  10,  17,  19,  34, 

73,  98 
Tamping  of  explosives,  108 
Taylor,  Gen.  Zachary,  quoted,  35 
Telegraph  lines,  74, 108, 109, 125, 131 
Telephone  lines,  32,  74,  108,  109,  125 
Terrain  exercises,  158 
Time  controlling  element  in  military 

engineering,  18, 19, 23, 26, 64 
Time  required  for  training  of  officers, 

9,  10 
Tools,     machines    and    gauges     in 

manufacture,  145 


Tools — see  Equipment,  23,  24,  25 
commercial  types,  28,  29 
intrenching  (portable),  25,  27, 

28,  29 
railroad,  32 
special  types,  29 

Towers,  suspension  bridge,  53 

Traffic: 

effect  of  grades,  67 
military,  nature  of,  64,  ^5 

Training,  military: 
in  Germany,  3 
in  Great  Britain,  5 

Training  of  civilian  volunteer  engi- 
neers, 10,  11,  17,  163 

Transit,  69 

Transportation,  3,  14,  142,  148 

Traverses,  84 

Trees,  69,  85,  92,  93,  99,  100,  112, 
127,  132 

Trenches — see  Field  fortification : 
communicating,  74,  88 
rifle,  74,  77,  78,  80,  81,  82 
support,  74 

Trenching  machines,  32,  33 

Trestle  bridges,  47,  48,  56 
portable,  37,  43 

Trinitrotoluol,  107 

Truss  bridges,  49,  50,  56 

Tunneling — see  Mining 

Typhoid  fever,  138,  139 

Type  plans  for  field  fortification,  97 

Undulations  of  suspension  bridRos, 

54 
Universal  training,  in  Germany,  3 

Ventilation : 

bomb-proofs,  88 
camp  sites,  138 
mine  galleries,  92 
roads,  69 


INDEX 


187 


Vertical  intervals,  119,  121 

Visibility  of  points  and  areas,  132, 
133 

Volunteer  army  required  in  case  of 
war,  6,  7 

Volunteer  engineers : 
commissions  in,  160 
training  of,  10,  11,  17 

Volunteers,    dependence   of   United 
States  on,  5 

Von  Moltke,  3 

Vulnerable  points  selected  for  demo- 
litions, 109,  110 

Wagons,  tool,  31 

Wanton  destruction,  not  justifiable, 
106 


War  the  field  of  the  expert,  2 
War,  cost  of,  18 

Wars  of  the  United  States,  unneces- 
sary cost  of,  1 
Water-borne  diseases,  139 
Water  supply — see  Camps,  125,  131, 

137 
Weapons  determine   characteristics 

of  fortification,  74,  75 
Weights,  of  ponton  equipage,  37,  40 
Wells,  139 
Widths: 

of  bridges,  56 
of  roads,  67 
Winches,  portable,  33 
Women,  employment  of,  in  indus- 
try, 146 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 

AN     INITIAL     FINE     OF     25     CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  50  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $100  ON  THE  SEVENTH  DAY 
OVERDUE. 


m  17  10^^ 


JUL16  1W& 

OCT  29  1937 
OCT  31    1938 

AUG  21  1942 


gSeV 


.itfit^* 


38 


9Npv'51LL 


LD  21-50m-l,'33 


J'fCt 


VB  04337 


3y^//^ 


13?  ' 


THE  UNIVERSITY  OF  CALIFORNIA  UBRARY 


/ 


